list Class

 

The STL list class is a template class of sequence containers that maintain their elements in a linear arrangement and allow efficient insertions and deletions at any location within the sequence. The sequence is stored as a bidirectional linked list of elements, each containing a member of some type Type.

template <class Type, class Allocator= allocator<Type>>  
class list  

Parameters

Type
The element data type to be stored in the list.

Allocator
The type that represents the stored allocator object that encapsulates details about the list's allocation and deallocation of memory. This argument is optional, and the default value is allocator< Type> .

The choice of container type should be based in general on the type of searching and inserting required by the application. Vectors should be the preferred container for managing a sequence when random access to any element is at a premium and insertions or deletions of elements are only required at the end of a sequence. The performance of the class deque container is superior when random access is needed and insertions and deletions at both the beginning and the end of a sequence are at a premium.

The list member functions merge, reverse, unique, remove, and remove_if have been optimized for operation on list objects and offer a high-performance alternative to their generic counterparts.

List reallocation occurs when a member function must insert or erase elements of the list. In all such cases, only iterators or references that point at erased portions of the controlled sequence become invalid.

Include the STL standard header <list> to define the container template class list and several supporting templates.

Constructors

listConstructs a list of a specific size or with elements of a specific value or with a specific allocator or as a copy of some other list.

Typedefs

allocator_typeA type that represents the allocator class for a list object.
const_iteratorA type that provides a bidirectional iterator that can read a const element in a list.
const_pointerA type that provides a pointer to a const element in a list.
const_referenceA type that provides a reference to a const element stored in a list for reading and performing const operations.
const_reverse_iteratorA type that provides a bidirectional iterator that can read any const element in a list.
difference_typeA type that provides the difference between two iterators that refer to elements within the same list.
iteratorA type that provides a bidirectional iterator that can read or modify any element in a list.
pointerA type that provides a pointer to an element in a list.
referenceA type that provides a reference to a const element stored in a list for reading and performing const operations.
reverse_iteratorA type that provides a bidirectional iterator that can read or modify an element in a reversed list.
size_typeA type that counts the number of elements in a list.
value_typeA type that represents the data type stored in a list.

Member Functions

assignErases elements from a list and copies a new set of elements to the target list.
backReturns a reference to the last element of a list.
beginReturns an iterator addressing the first element in a list.
list::cbeginReturns a const iterator addressing the first element in a list.
list::cendReturns a const iterator that addresses the location succeeding the last element in a list.
list::clearErases all the elements of a list.
list::crbeginReturns a const iterator addressing the first element in a reversed list.
list::crendReturns a const iterator that addresses the location succeeding the last element in a reversed list.
list::emplaceInserts an element constructed in place into a list at a specified position.
list::emplace_backAdds an element constructed in place to the end of a list.
list::emplace_frontAdds an element constructed in place to the beginning of a list.
emptyTests if a list is empty.
endReturns an iterator that addresses the location succeeding the last element in a list.
eraseRemoves an element or a range of elements in a list from specified positions.
frontReturns a reference to the first element in a list.
get_allocatorReturns a copy of the allocator object used to construct a list.
insertInserts an element or a number of elements or a range of elements into a list at a specified position.
max_sizeReturns the maximum length of a list.
mergeRemoves the elements from the argument list, inserts them into the target list, and orders the new, combined set of elements in ascending order or in some other specified order.
pop_backDeletes the element at the end of a list.
pop_frontDeletes the element at the beginning of a list.
push_backAdds an element to the end of a list.
push_frontAdds an element to the beginning of a list.
rbeginReturns an iterator addressing the first element in a reversed list.
removeErases elements in a list that match a specified value.
remove_ifErases elements from the list for which a specified predicate is satisfied.
rendReturns an iterator that addresses the location succeeding the last element in a reversed list.
resizeSpecifies a new size for a list.
reverseReverses the order in which the elements occur in a list.
sizeReturns the number of elements in a list.
sortArranges the elements of a list in ascending order or with respect to some other order relation.
spliceRemoves elements from the argument list and inserts them into the target list.
swapExchanges the elements of two lists.
uniqueRemoves adjacent duplicate elements or adjacent elements that satisfy some other binary predicate from the list.

Operators

list::operator=Replaces the elements of the list with a copy of another list.

Header: <list>

A type that represents the allocator class for a list object.

typedef Allocator allocator_type;  

Remarks

allocator_type is a synonym for the template parameter Allocator.

Example

See the example for get_allocator.

Erases elements from a list and copies a new set of elements to a target list.

void assign(
    size_type Count,  
    const Type& Val);

void assign  
    initializer_list<Type> IList);

template <class InputIterator>  
void assign(
    InputIterator First,  
    InputIterator Last);

Parameters

First
Position of the first element in the range of elements to be copied from the argument list.

Last
Position of the first element just beyond the range of elements to be copied from the argument list.

Count
The number of copies of an element being inserted into the list.

Val
The value of the element being inserted into the list.

IList
The initializer_list that contains the elements to be inserted.

Remarks

After erasing any existing elements in the target list, assign either inserts a specified range of elements from the original list or from some other list into the target list or inserts copies of a new element of a specified value into the target list

Example

// list_assign.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main()  
{  
    using namespace std;  
    list<int> c1, c2;  
    list<int>::const_iterator cIter;  
  
    c1.push_back(10);  
    c1.push_back(20);  
    c1.push_back(30);  
    c2.push_back(40);  
    c2.push_back(50);  
    c2.push_back(60);  
  
    cout << "c1 =";  
    for (auto c : c1)  
        cout << " " << c;  
    cout << endl;  
  
    c1.assign(++c2.begin(), c2.end());  
    cout << "c1 =";  
    for (auto c : c1)  
        cout << " " << c;  
    cout << endl;  
  
    c1.assign(7, 4);  
    cout << "c1 =";  
    for (auto c : c1)  
        cout << " " << c;  
    cout << endl;  
  
    c1.assign({ 10, 20, 30, 40 });  
    cout << "c1 =";  
    for (auto c : c1)  
        cout << " " << c;  
    cout << endl;  
}  

c1 = 10 20 30c1 = 50 60c1 = 4 4 4 4 4 4 4c1 = 10 20 30 40  

Returns a reference to the last element of a list.

reference back();

const_reference back() const;

Return Value

The last element of the list. If the list is empty, the return value is undefined.

Remarks

If the return value of back is assigned to a const_reference, the list object cannot be modified. If the return value of back is assigned to a reference, the list object can be modified.

When compiling with _SECURE_SCL 1, a runtime error will occur if you attempt to access an element in an empty list. See Checked Iterators for more information.

Example

// list_back.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
  
   c1.push_back( 10 );  
   c1.push_back( 11 );  
  
   int& i = c1.back( );  
   const int& ii = c1.front( );  
  
   cout << "The last integer of c1 is " << i << endl;  
   i--;  
   cout << "The next-to-last integer of c1 is " << ii << endl;  
}  

The last integer of c1 is 11  
The next-to-last integer of c1 is 10  

Returns an iterator addressing the first element in a list.

const_iterator begin() const;

iterator begin();

Return Value

A bidirectional iterator addressing the first element in the list or to the location succeeding an empty list.

Remarks

If the return value of begin is assigned to a const_iterator, the elements in the list object cannot be modified. If the return value of begin is assigned to an iterator, the elements in the list object can be modified.

Example

// list_begin.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
   list <int>::iterator c1_Iter;  
   list <int>::const_iterator c1_cIter;  
  
   c1.push_back( 1 );  
   c1.push_back( 2 );  
  
   c1_Iter = c1.begin( );  
   cout << "The first element of c1 is " << *c1_Iter << endl;  
  
 *c1_Iter = 20;  
   c1_Iter = c1.begin( );  
   cout << "The first element of c1 is now " << *c1_Iter << endl;  
  
   // The following line would be an error because iterator is const  
   // *c1_cIter = 200;  
}  

The first element of c1 is 1  
The first element of c1 is now 20  

Returns a const iterator that addresses the first element in the range.

const_iterator cbegin() const;

Return Value

A const bidirectional-access iterator that points at the first element of the range, or the location just beyond the end of an empty range (for an empty range, cbegin() == cend()).

Remarks

With the return value of cbegin, the elements in the range cannot be modified.

You can use this member function in place of the begin() member function to guarantee that the return value is const_iterator. Typically, it's used in conjunction with the auto type deduction keyword, as shown in the following example. In the example, consider Container to be a modifiable (non- const) container of any kind that supports begin() and cbegin().

 
auto i1 = Container.begin();
// i1 is Container<T>::iterator   
auto i2 = Container.cbegin();

// i2 is Container<T>::const_iterator  

Returns a const iterator that addresses the location just beyond the last element in a range.

const_iterator cend() const;

Return Value

A const bidirectional-access iterator that points just beyond the end of the range.

Remarks

cend is used to test whether an iterator has passed the end of its range.

You can use this member function in place of the end() member function to guarantee that the return value is const_iterator. Typically, it's used in conjunction with the auto type deduction keyword, as shown in the following example. In the example, consider Container to be a modifiable (non- const) container of any kind that supports end() and cend().

 
auto i1 = Container.end();
// i1 is Container<T>::iterator   
auto i2 = Container.cend();

// i2 is Container<T>::const_iterator  

The value returned by cend should not be dereferenced.

Erases all the elements of a list.

void clear();

Example

// list_clear.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main() {  
   using namespace std;  
   list <int> c1;  
  
   c1.push_back( 10 );  
   c1.push_back( 20 );  
   c1.push_back( 30 );  
  
   cout << "The size of the list is initially " << c1.size( ) << endl;  
   c1.clear( );  
   cout << "The size of list after clearing is " << c1.size( ) << endl;  
}  

The size of the list is initially 3  
The size of list after clearing is 0  

A type that provides a bidirectional iterator that can read a const element in a list.

typedef implementation-defined const_iterator;  

Remarks

A type const_iterator cannot be used to modify the value of an element.

Example

See the example for back.

Provides a pointer to a const element in a list.

typedef typename Allocator::const_pointer const_pointer;  

Remarks

A type const_pointer cannot be used to modify the value of an element.

In most cases, an iterator should be used to access the elements in a list object.

A type that provides a reference to a const element stored in a list for reading and performing const operations.

typedef typename Allocator::const_reference const_reference;  

Remarks

A type const_reference cannot be used to modify the value of an element.

Example

// list_const_ref.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
  
   c1.push_back( 10 );  
   c1.push_back( 20 );  
  
   const list <int> c2 = c1;  
   const int &i = c2.front( );  
   const int &j = c2.back( );  
   cout << "The first element is " << i << endl;  
   cout << "The second element is " << j << endl;  
  
   // The following line would cause an error because c2 is const  
   // c2.push_back( 30 );  
}  

The first element is 10  
The second element is 20  

A type that provides a bidirectional iterator that can read any const element in a list.

typedef std::reverse_iterator<const_iterator> const_reverse_iterator;  

Remarks

A type const_reverse_iterator cannot modify the value of an element and is used to iterate through the list in reverse.

Example

See the example for rbegin.

Returns a const iterator addressing the first element in a reversed list.

const_reverse_iterator rbegin() const;

Return Value

A const reverse bidirectional iterator addressing the first element in a reversed list (or addressing what had been the last element in the unreversed list).

Remarks

crbegin is used with a reversed list just as list::begin is used with a list.

With the return value of crbegin, the list object cannot be modified. list::rbegin can be used to iterate through a list backwards.

Example

// list_crbegin.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
   list <int>::const_reverse_iterator c1_crIter;  
  
   c1.push_back( 10 );  
   c1.push_back( 20 );  
   c1.push_back( 30 );  
   c1_crIter = c1.crbegin( );  
   cout << "The last element in the list is " << *c1_crIter << "." << endl;  
}  

The last element in the list is 30.  

Returns a const iterator that addresses the location succeeding the last element in a reversed list.

const_reverse_iterator rend() const;

Return Value

A const reverse bidirectional iterator that addresses the location succeeding the last element in a reversed list (the location that had preceded the first element in the unreversed list).

Remarks

crend is used with a reversed list just as list::end is used with a list.

With the return value of crend, the list object cannot be modified.

crend can be used to test to whether a reverse iterator has reached the end of its list.

The value returned by crend should not be dereferenced.

Example

// list_crend.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
   list <int>::const_reverse_iterator c1_crIter;  
  
   c1.push_back( 10 );  
   c1.push_back( 20 );  
   c1.push_back( 30 );  
  
   c1_crIter = c1.crend( );  
   c1_crIter --;  // Decrementing a reverse iterator moves it forward in   
                 // the list (to point to the first element here)  
   cout << "The first element in the list is: " << *c1_crIter << endl;  
}  

The first element in the list is: 10  

A signed integer type that can be used to represent the number of elements of a list in a range between elements pointed to by iterators.

typedef typename Allocator::difference_type difference_type;  

Remarks

The difference_type is the type returned when subtracting or incrementing through iterators of the container. The difference_type is typically used to represent the number of elements in the range [ first, last) between the iterators first and last, includes the element pointed to by first and the range of elements up to, but not including, the element pointed to by last.

Note that although difference_type is available for all iterators that satisfy the requirements of an input iterator, which includes the class of bidirectional iterators supported by reversible containers like set, subtraction between iterators is only supported by random-access iterators provided by a random-access container, such as vector Class.

Example

// list_diff_type.cpp  
// compile with: /EHsc  
#include <iostream>  
#include <list>  
#include <algorithm>  
  
int main( )   
{  
   using namespace std;  
  
   list <int> c1;  
   list <int>::iterator   c1_Iter, c2_Iter;  
  
   c1.push_back( 30 );  
   c1.push_back( 20 );  
   c1.push_back( 30 );  
   c1.push_back( 10 );  
   c1.push_back( 30 );  
   c1.push_back( 20 );  
  
   c1_Iter = c1.begin( );  
   c2_Iter = c1.end( );  
  
    list <int>::difference_type df_typ1, df_typ2, df_typ3;  
  
   df_typ1 = count( c1_Iter, c2_Iter, 10 );  
   df_typ2 = count( c1_Iter, c2_Iter, 20 );  
   df_typ3 = count( c1_Iter, c2_Iter, 30 );  
   cout << "The number '10' is in c1 collection " << df_typ1 << " times.\n";  
   cout << "The number '20' is in c1 collection " << df_typ2 << " times.\n";  
   cout << "The number '30' is in c1 collection " << df_typ3 << " times.\n";  
}  

The number '10' is in c1 collection 1 times.  
The number '20' is in c1 collection 2 times.  
The number '30' is in c1 collection 3 times.  

Inserts an element constructed in place into a list at a specified position.

void emplace_back(iterator _Where, Type&& val);

Parameters

ParameterDescription
_WhereThe position in the target list where the first element is inserted.
valThe element added to the end of the list.

Remarks

If an exception is thrown, the list is left unaltered and the exception is rethrown.

Example

// list_emplace.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
#include <string>  
  
int main( )   
{  
   using namespace std;  
   list <string> c2;  
   string str("a");  
  
   c2.emplace(c2.begin(), move( str ) );  
   cout << "Moved first element: " << c2.back( ) << endl;  
}  

Moved first element: a  

Adds an element constructed in place to the beginning of a list.

void emplace_back(Type&& val);

Parameters

ParameterDescription
valThe element added to the end of the list.

Remarks

If an exception is thrown, the list is left unaltered and the exception is rethrown.

Example

// list_emplace_back.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
#include <string>  
  
int main( )   
{  
   using namespace std;  
   list <string> c2;  
   string str("a");  
  
   c2.emplace_back( move( str ) );  
   cout << "Moved first element: " << c2.back( ) << endl;  
}  

Moved first element: a  

Adds an element constructed in place to the beginning of a list.

void emplace_front(Type&& val);

Parameters

ParameterDescription
valThe element added to the beginning of the list.

Remarks

If an exception is thrown, the list is left unaltered and the exception is rethrown.

Example

// list_emplace_front.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
#include <string>  
  
int main( )   
{  
   using namespace std;  
   list <string> c2;  
   string str("a");  
  
   c2.emplace_front( move( str ) );  
   cout << "Moved first element: " << c2.front( ) << endl;  
}  

Moved first element: a  

Tests if a list is empty.

bool empty() const;

Return Value

true if the list is empty; false if the list is not empty.

Example

// list_empty.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )  
{  
   using namespace std;  
   list <int> c1;  
  
   c1.push_back( 10 );  
   if ( c1.empty( ) )  
      cout << "The list is empty." << endl;  
   else  
      cout << "The list is not empty." << endl;  
}  

The list is not empty.  

Returns an iterator that addresses the location succeeding the last element in a list.

const_iterator end() const;

iterator end();

Return Value

A bidirectional iterator that addresses the location succeeding the last element in a list. If the list is empty, then list::end == list::begin.

Remarks

end is used to test whether an iterator has reached the end of its list.

Example

// list_end.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
   list <int>::iterator c1_Iter;  
  
   c1.push_back( 10 );  
   c1.push_back( 20 );  
   c1.push_back( 30 );  
  
   c1_Iter = c1.end( );  
   c1_Iter--;  
   cout << "The last integer of c1 is " << *c1_Iter << endl;  
  
   c1_Iter--;  
 *c1_Iter = 400;  
   cout << "The new next-to-last integer of c1 is "  
        << *c1_Iter << endl;  
  
   // If a const iterator had been declared instead with the line:  
   // list <int>::const_iterator c1_Iter;  
   // an error would have resulted when inserting the 400  
  
   cout << "The list is now:";  
   for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )  
      cout << " " << *c1_Iter;  
}  

The last integer of c1 is 30  
The new next-to-last integer of c1 is 400  
The list is now: 10 400 30  

Removes an element or a range of elements in a list from specified positions.

iterator erase(iterator _Where);

iterator erase(iterator first, iterator last);

Parameters

_Where
Position of the element to be removed from the list.

first
Position of the first element removed from the list.

last
Position just beyond the last element removed from the list.

Return Value

A bidirectional iterator that designates the first element remaining beyond any elements removed, or a pointer to the end of the list if no such element exists.

Remarks

No reallocation occurs, so iterators and references become invalid only for the erased elements.

erase never throws an exception.

Example

// list_erase.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
   list <int>::iterator Iter;  
  
   c1.push_back( 10 );  
   c1.push_back( 20 );  
   c1.push_back( 30 );  
   c1.push_back( 40 );  
   c1.push_back( 50 );  
   cout << "The initial list is:";  
   for ( Iter = c1.begin( ); Iter != c1.end( ); Iter++ )  
      cout << " " << *Iter;  
   cout << endl;  
  
   c1.erase( c1.begin( ) );  
   cout << "After erasing the first element, the list becomes:";  
   for ( Iter = c1.begin( ); Iter != c1.end( ); Iter++ )  
      cout << " " << *Iter;  
   cout << endl;  
   Iter = c1.begin( );  
   Iter++;  
   c1.erase( Iter, c1.end( ) );  
   cout << "After erasing all elements but the first, the list becomes: ";  
   for (Iter = c1.begin( ); Iter != c1.end( ); Iter++ )  
      cout << " " << *Iter;  
   cout << endl;  
}  

The initial list is: 10 20 30 40 50  
After erasing the first element, the list becomes: 20 30 40 50  
After erasing all elements but the first, the list becomes:  20  

Returns a reference to the first element in a list.

reference front();

const_reference front() const;

Return Value

If the list is empty, the return is undefined.

Remarks

If the return value of front is assigned to a const_reference, the list object cannot be modified. If the return value of front is assigned to a reference, the list object can be modified.

When compiling with _SECURE_SCL 1, a runtime error will occur if you attempt to access an element in an empty list. See Checked Iterators for more information.

Example

// list_front.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main() {  
   using namespace std;  
   list <int> c1;  
  
   c1.push_back( 10 );  
  
   int& i = c1.front();  
   const int& ii = c1.front();  
  
   cout << "The first integer of c1 is " << i << endl;  
   i++;  
   cout << "The first integer of c1 is " << ii << endl;  
}  

The first integer of c1 is 10  
The first integer of c1 is 11  

Returns a copy of the allocator object used to construct a list.

Allocator get_allocator() const;

Return Value

The allocator used by the list.

Remarks

Allocators for the list class specify how the class manages storage. The default allocators supplied with STL container classes are sufficient for most programming needs. Writing and using your own allocator class is an advanced C++ topic.

Example

// list_get_allocator.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   // The following lines declare objects   
   // that use the default allocator.  
   list <int> c1;  
   list <int, allocator<int> > c2 = list <int, allocator<int> >( allocator<int>( ) );  
  
   // c3 will use the same allocator class as c1  
   list <int> c3( c1.get_allocator( ) );  
  
   list<int>::allocator_type xlst = c1.get_allocator( );  
   // You can now call functions on the allocator class used by c1  
}  

Inserts an element or a number of elements or a range of elements into a list at a specified position.

iterator insert(
    iterator Where,  
    const Type& Val);

iterator insert(
    iterator Where,  
    Type&& Val);

void insert(
    iterator Where,  
    size_type Count,  
    const Type& Val);

iterator insert(
    iterator Where,  
    initializer_list<Type> IList);

template <class InputIterator>  
void insert(
    iterator Where,  
    InputIterator First,  
    InputIterator Last);

Parameters

ParameterDescription
WhereThe position in the target list where the first element is inserted.
ValThe value of the element being inserted into the list.
CountThe number of elements being inserted into the list.
FirstThe position of the first element in the range of elements in the argument list to be copied.
LastThe position of the first element beyond the range of elements in the argument list to be copied.

Return Value

The first two insert functions return an iterator that points to the position where the new element was inserted into the list.

Example

// list_class_insert.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
#include <string>  
  
int main()  
{  
    using namespace std;  
    list <int> c1, c2;  
    list <int>::iterator Iter;  
  
    c1.push_back(10);  
    c1.push_back(20);  
    c1.push_back(30);  
    c2.push_back(40);  
    c2.push_back(50);  
    c2.push_back(60);  
  
    cout << "c1 =";  
    for (auto c : c1)  
        cout << " " << c;  
    cout << endl;  
  
    Iter = c1.begin();  
    Iter++;  
    c1.insert(Iter, 100);  
    cout << "c1 =";  
    for (auto c : c1)  
        cout << " " << c;  
    cout << endl;  
  
    Iter = c1.begin();  
    Iter++;  
    Iter++;  
    c1.insert(Iter, 2, 200);  
  
    cout << "c1 =";  
    for(auto c : c1)  
        cout << " " << c;  
    cout << endl;  
  
    c1.insert(++c1.begin(), c2.begin(), --c2.end());  
  
    cout << "c1 =";  
    for (auto c : c1)  
        cout << " " << c;  
    cout << endl;  
  
    // initialize a list of strings by moving  
    list < string > c3;  
    string str("a");  
  
    c3.insert(c3.begin(), move(str));  
    cout << "Moved first element: " << c3.front() << endl;  
  
    // Assign with an initializer_list  
    list <int> c4{ {1, 2, 3, 4} };  
    c4.insert(c4.begin(), { 5, 6, 7, 8 });  
  
    cout << "c4 =";  
    for (auto c : c4)  
        cout << " " << c;  
    cout << endl;  
}  

A type that provides a bidirectional iterator that can read or modify any element in a list.

typedef implementation-defined iterator;  

Remarks

A type iterator can be used to modify the value of an element.

Example

See the example for begin.

Constructs a list of a specific size or with elements of a specific value or with a specific allocator or as a copy of all or part of some other list.

list();

explicit list(
    const Allocator& Al);

explicit list(
    size_type Count);

list(
    size_type Count,  
    const Type& Val);

list(
    size_type Count,  
    const Type& Val,  
    const Allocator& Al);

list(
    const list& Right);

list(
    list&& Right);

list(
    initializer_list<Type> IList,  
    const Allocator& Al);

template <class InputIterator>  
list(
 InputIterator First,  
    InputIterator Last);

template <class InputIterator>  
list(
 InputIterator First,  
    InputIterator Last,  
    const Allocator& Al);

Parameters

ParameterDescription
AlThe allocator class to use with this object.
CountThe number of elements in the list constructed.
ValThe value of the elements in the list.
RightThe list of which the constructed list is to be a copy.
FirstThe position of the first element in the range of elements to be copied.
LastThe position of the first element beyond the range of elements to be copied.
IListThe initializer_list that contains the elements to be copied.

Remarks

All constructors store an allocator object ( Al) and initialize the list.

get_allocator returns a copy of the allocator object used to construct a list.

The first two constructors specify an empty initial list, the second specifying the allocator type ( Al) to be used.

The third constructor specifies a repetition of a specified number ( Count) of elements of the default value for class Type.

The fourth and fifth constructors specify a repetition of ( Count) elements of value Val.

The sixth constructor specifies a copy of the list Right.

The seventh constructor moves the list Right.

The eighth constructor uses an initializer_list to specify the elements.

The next two constructors copy the range [First, Last) of a list.

None of the constructors perform any interim reallocations.

Example

// list_class_list.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main()  
{  
    using namespace std;  
    // Create an empty list c0  
    list <int> c0;  
  
    // Create a list c1 with 3 elements of default value 0  
    list <int> c1(3);  
  
    // Create a list c2 with 5 elements of value 2  
    list <int> c2(5, 2);  
  
    // Create a list c3 with 3 elements of value 1 and with the   
    // allocator of list c2  
    list <int> c3(3, 1, c2.get_allocator());  
  
    // Create a copy, list c4, of list c2  
    list <int> c4(c2);  
  
    // Create a list c5 by copying the range c4[ first,  last)  
    list <int>::iterator c4_Iter = c4.begin();  
    c4_Iter++;  
    c4_Iter++;  
    list <int> c5(c4.begin(), c4_Iter);  
  
    // Create a list c6 by copying the range c4[ first,  last) and with   
    // the allocator of list c2  
    c4_Iter = c4.begin();  
    c4_Iter++;  
    c4_Iter++;  
    c4_Iter++;  
    list <int> c6(c4.begin(), c4_Iter, c2.get_allocator());  
  
    cout << "c1 =";  
    for (auto c : c1)  
        cout << " " << c;  
    cout << endl;  
  
    cout << "c2 =";  
    for (auto c : c2)  
        cout << " " << c;  
    cout << endl;  
  
    cout << "c3 =";  
    for (auto c : c3)  
        cout << " " << c;  
    cout << endl;  
  
    cout << "c4 =";  
    for (auto c : c4)  
        cout << " " << c;  
    cout << endl;  
  
    cout << "c5 =";  
    for (auto c : c5)  
        cout << " " << c;  
    cout << endl;  
  
    cout << "c6 =";  
    for (auto c : c6)  
        cout << " " << c;  
    cout << endl;  
  
    // Move list c6 to list c7  
    list <int> c7(move(c6));  
    cout << "c7 =";  
    for (auto c : c7)  
        cout << " " << c;  
    cout << endl;  
  
    // Construct with initializer_list  
    list<int> c8({ 1, 2, 3, 4 });  
    cout << "c8 =";  
    for (auto c : c8)  
        cout << " " << c;  
    cout << endl;  
}  

c1 = 0 0 0c2 = 2 2 2 2 2c3 = 1 1 1c4 = 2 2 2 2 2c5 = 2 2c6 = 2 2 2c7 = 2 2 2c8 = 1 2 3 4  

Returns the maximum length of a list.

size_type max_size() const;

Return Value

The maximum possible length of the list.

Example

// list_max_size.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
   list <int>::size_type i;  
  
   i = c1.max_size( );  
   cout << "Maximum possible length of the list is " << i << "." << endl;  
}  

Removes the elements from the argument list, inserts them into the target list, and orders the new, combined set of elements in ascending order or in some other specified order.

void merge(
    list<Type, Allocator>& right);

template <class Traits>  
void merge(
    list<Type, Allocator>& right,   
    Traits comp);

Parameters

right
The argument list to be merged with the target list.

comp
The comparison operator used to order the elements of the target list.

Remarks

The argument list right is merged with the target list.

Both argument and target lists must be ordered with the same comparison relation by which the resulting sequence is to be ordered. The default order for the first member function is ascending order. The second member function imposes the user-specified comparison operation comp of class Traits.

Example

// list_merge.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1, c2, c3;  
   list <int>::iterator c1_Iter, c2_Iter, c3_Iter;  
  
   c1.push_back( 3 );  
   c1.push_back( 6 );  
   c2.push_back( 2 );  
   c2.push_back( 4 );  
   c3.push_back( 5 );  
   c3.push_back( 1 );  
  
   cout << "c1 =";  
   for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )  
      cout << " " << *c1_Iter;  
   cout << endl;  
  
   cout << "c2 =";  
   for ( c2_Iter = c2.begin( ); c2_Iter != c2.end( ); c2_Iter++ )  
      cout << " " << *c2_Iter;  
   cout << endl;  
  
   c2.merge( c1 );  // Merge c1 into c2 in (default) ascending order  
   c2.sort( greater<int>( ) );  
   cout << "After merging c1 with c2 and sorting with >: c2 =";  
   for ( c2_Iter = c2.begin( ); c2_Iter != c2.end( ); c2_Iter++ )  
      cout << " " << *c2_Iter;  
   cout << endl;  
  
   cout << "c3 =";  
   for ( c3_Iter = c3.begin( ); c3_Iter != c3.end( ); c3_Iter++ )  
      cout << " " << *c3_Iter;  
   cout << endl;  
  
   c2.merge( c3, greater<int>( ) );  
   cout << "After merging c3 with c2 according to the '>' comparison relation: c2 =";  
   for ( c2_Iter = c2.begin( ); c2_Iter != c2.end( ); c2_Iter++ )  
      cout << " " << *c2_Iter;  
   cout << endl;  
}  

c1 = 3 6  
c2 = 2 4  
After merging c1 with c2 and sorting with >: c2 = 6 4 3 2  
c3 = 5 1  
After merging c3 with c2 according to the '>' comparison relation: c2 = 6 5 4 3 2 1  

Replaces the elements of the list with a copy of another list.

list& operator=(const list& right);

list& operator=(list&& right);

Parameters

ParameterDescription
rightThe list being copied into the list.

Remarks

After erasing any existing elements in a list, the operator either copies or moves the contents of right into the list.

Example

// list_operator_as.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )  
{  
   using namespace std;  
   list<int> v1, v2, v3;  
   list<int>::iterator iter;  
  
   v1.push_back(10);  
   v1.push_back(20);  
   v1.push_back(30);  
   v1.push_back(40);  
   v1.push_back(50);  
  
   cout << "v1 = " ;  
   for (iter = v1.begin(); iter != v1.end(); iter++)  
      cout << *iter << " ";  
   cout << endl;  
  
   v2 = v1;  
   cout << "v2 = ";  
   for (iter = v2.begin(); iter != v2.end(); iter++)  
      cout << *iter << " ";  
   cout << endl;  
  
// move v1 into v2  
   v2.clear();  
   v2 = forward< list<int> >(v1);  
   cout << "v2 = ";  
   for (iter = v2.begin(); iter != v2.end(); iter++)  
      cout << *iter << " ";  
   cout << endl;  
}  

Provides a pointer to an element in a list.

typedef typename Allocator::pointer pointer;  

Remarks

A type pointer can be used to modify the value of an element.

In most cases, an iterator should be used to access the elements in a list object.

Deletes the element at the end of a list.

void pop_back();

Remarks

The last element must not be empty. pop_back never throws an exception.

Example

// list_pop_back.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
  
   c1.push_back( 1 );  
   c1.push_back( 2 );  
   cout << "The first element is: " << c1.front( ) << endl;  
   cout << "The last element is: " << c1.back( ) << endl;  
  
   c1.pop_back( );  
   cout << "After deleting the element at the end of the list, "  
           "the last element is: " << c1.back( ) << endl;  
}  

The first element is: 1  
The last element is: 2  
After deleting the element at the end of the list, the last element is: 1  

Deletes the element at the beginning of a list.

void pop_front();

Remarks

The first element must not be empty. pop_front never throws an exception.

Example

// list_pop_front.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
  
   c1.push_back( 1 );  
   c1.push_back( 2 );  
   cout << "The first element is: " << c1.front( ) << endl;  
   cout << "The second element is: " << c1.back( ) << endl;  
  
   c1.pop_front( );  
   cout << "After deleting the element at the beginning of the list, "  
         "the first element is: " << c1.front( ) << endl;  
}  

The first element is: 1  
The second element is: 2  
After deleting the element at the beginning of the list, the first element is: 2  

Adds an element to the end of a list.

void push_back(void push_back(Type&& val);

Parameters

ParameterDescription
valThe element added to the end of the list.

Remarks

If an exception is thrown, the list is left unaltered and the exception is rethrown.

Example

// list_push_back.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
#include <string>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
  
   c1.push_back( 1 );  
   if ( c1.size( ) != 0 )  
      cout << "Last element: " << c1.back( ) << endl;  
  
   c1.push_back( 2 );  
   if ( c1.size( ) != 0 )  
      cout << "New last element: " << c1.back( ) << endl;  
  
// move initialize a list of strings  
   list <string> c2;  
   string str("a");  
  
   c2.push_back( move( str ) );  
   cout << "Moved first element: " << c2.back( ) << endl;  
}  

Last element: 1  
New last element: 2  
Moved first element: a  

Adds an element to the beginning of a list.

void push_front(const Type& val);

void push_front(Type&& val);

Parameters

ParameterDescription
valThe element added to the beginning of the list.

Remarks

If an exception is thrown, the list is left unaltered and the exception is rethrown.

Example

// list_push_front.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
#include <string>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
  
   c1.push_front( 1 );  
   if ( c1.size( ) != 0 )  
      cout << "First element: " << c1.front( ) << endl;  
  
   c1.push_front( 2 );  
   if ( c1.size( ) != 0 )  
      cout << "New first element: " << c1.front( ) << endl;  
  
// move initialize a list of strings  
   list <string> c2;  
   string str("a");  
  
   c2.push_front( move( str ) );  
   cout << "Moved first element: " << c2.front( ) << endl;  
}  

First element: 1  
New first element: 2  
Moved first element: a  

Returns an iterator that addresses the first element in a reversed list.

const_reverse_iterator rbegin() const;

reverse_iterator rbegin();

Return Value

A reverse bidirectional iterator addressing the first element in a reversed list (or addressing what had been the last element in the unreversed list).

Remarks

rbegin is used with a reversed list just as begin is used with a list.

If the return value of rbegin is assigned to a const_reverse_iterator, the list object cannot be modified. If the return value of rbegin is assigned to a reverse_iterator, the list object can be modified.

rbegin can be used to iterate through a list backwards.

Example

// list_rbegin.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
   list <int>::iterator c1_Iter;  
   list <int>::reverse_iterator c1_rIter;  
  
   // If the following line replaced the line above, *c1_rIter = 40;  
   // (below) would be an error  
   //list <int>::const_reverse_iterator c1_rIter;  
  
   c1.push_back( 10 );  
   c1.push_back( 20 );  
   c1.push_back( 30 );  
   c1_rIter = c1.rbegin( );  
   cout << "The last element in the list is " << *c1_rIter << "." << endl;  
  
   cout << "The list is:";  
   for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )  
      cout << " " << *c1_Iter;  
   cout << endl;  
  
   // rbegin can be used to start an iteration through a list in   
   // reverse order  
   cout << "The reversed list is:";  
   for ( c1_rIter = c1.rbegin( ); c1_rIter != c1.rend( ); c1_rIter++ )  
      cout << " " << *c1_rIter;  
   cout << endl;  
  
   c1_rIter = c1.rbegin( );  
 *c1_rIter = 40;  
   cout << "The last element in the list is now " << *c1_rIter << "." << endl;  
}  

The last element in the list is 30.  
The list is: 10 20 30  
The reversed list is: 30 20 10  
The last element in the list is now 40.  

A type that provides a reference to an element stored in a list.

typedef typename Allocator::reference reference;  

Example

// list_ref.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
  
   c1.push_back( 10 );  
   c1.push_back( 20 );  
  
   int &i = c1.front( );  
   int &j = c1.back( );  
   cout << "The first element is " << i << endl;  
   cout << "The second element is " << j << endl;  
}  

The first element is 10  
The second element is 20  

Erases elements in a list that match a specified value.

void remove(const Type& val);

Parameters

val
The value which, if held by an element, will result in that element's removal from the list.

Remarks

The order of the elements remaining is not affected.

Example

// list_remove.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
   list <int>::iterator c1_Iter, c2_Iter;  
  
   c1.push_back( 5 );  
   c1.push_back( 100 );  
   c1.push_back( 5 );  
   c1.push_back( 200 );  
   c1.push_back( 5 );  
   c1.push_back( 300 );  
  
   cout << "The initial list is c1 =";  
   for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )  
      cout << " " << *c1_Iter;  
   cout << endl;  
  
   list <int> c2 = c1;  
   c2.remove( 5 );  
   cout << "After removing elements with value 5, the list becomes c2 =";  
   for ( c2_Iter = c2.begin( ); c2_Iter != c2.end( ); c2_Iter++ )  
      cout << " " << *c2_Iter;  
   cout << endl;  
}  

The initial list is c1 = 5 100 5 200 5 300  
After removing elements with value 5, the list becomes c2 = 100 200 300  

Erases elements from a list for which a specified predicate is satisfied.

template <class Predicate>  
void remove_if(Predicate pred)  

Parameters

pred
The unary predicate which, if satisfied by an element, results in the deletion of that element from the list.

Example

// list_remove_if.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
template <class T> class is_odd : public std::unary_function<T, bool>   
{  
public:  
   bool operator( ) ( T& val )   
   {  
   return ( val % 2 ) == 1;  
   }  
};  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
   list <int>::iterator c1_Iter, c2_Iter;  
  
   c1.push_back( 3 );  
   c1.push_back( 4 );  
   c1.push_back( 5 );  
   c1.push_back( 6 );  
   c1.push_back( 7 );  
   c1.push_back( 8 );  
  
   cout << "The initial list is c1 =";  
   for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )  
      cout << " " << *c1_Iter;  
   cout << endl;  
  
   list <int> c2 = c1;  
   c2.remove_if( is_odd<int>( ) );  
  
   cout << "After removing the odd elements, "  
        << "the list becomes c2 =";  
   for ( c2_Iter = c2.begin( ); c2_Iter != c2.end( ); c2_Iter++ )  
      cout << " " << *c2_Iter;  
   cout << endl;  
}  

The initial list is c1 = 3 4 5 6 7 8  
After removing the odd elements, the list becomes c2 = 4 6 8  

Returns an iterator that addresses the location that follows the last element in a reversed list.

const_reverse_iterator rend() const;

reverse_iterator rend();

Return Value

A reverse bidirectional iterator that addresses the location succeeding the last element in a reversed list (the location that had preceded the first element in the unreversed list).

Remarks

rend is used with a reversed list just as end is used with a list.

If the return value of rend is assigned to a const_reverse_iterator, the list object cannot be modified. If the return value of rend is assigned to a reverse_iterator, the list object can be modified.

rend can be used to test to whether a reverse iterator has reached the end of its list.

The value returned by rend should not be dereferenced.

Example

// list_rend.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
   list <int>::iterator c1_Iter;  
   list <int>::reverse_iterator c1_rIter;  
  
   // If the following line had replaced the line above, an error would   
   // have resulted in the line modifying an element (commented below)  
   // because the iterator would have been const  
   // list <int>::const_reverse_iterator c1_rIter;  
  
   c1.push_back( 10 );  
   c1.push_back( 20 );  
   c1.push_back( 30 );  
  
   c1_rIter = c1.rend( );  
   c1_rIter --;  // Decrementing a reverse iterator moves it forward in   
                 // the list (to point to the first element here)  
   cout << "The first element in the list is: " << *c1_rIter << endl;  
  
   cout << "The list is:";  
   for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )  
      cout << " " << *c1_Iter;  
   cout << endl;  
  
   // rend can be used to test if an iteration is through all of the   
   // elements of a reversed list  
   cout << "The reversed list is:";  
   for ( c1_rIter = c1.rbegin( ); c1_rIter != c1.rend( ); c1_rIter++ )  
      cout << " " << *c1_rIter;  
   cout << endl;  
  
   c1_rIter = c1.rend( );  
   c1_rIter--;  // Decrementing the reverse iterator moves it backward   
                // in the reversed list (to the last element here)  
  
 *c1_rIter = 40;  // This modification of the last element would have   
                    // caused an error if a const_reverse iterator had   
                    // been declared (as noted above)  
  
   cout << "The modified reversed list is:";  
   for ( c1_rIter = c1.rbegin( ); c1_rIter != c1.rend( ); c1_rIter++ )  
      cout << " " << *c1_rIter;  
   cout << endl;  
}  

The first element in the list is: 10  
The list is: 10 20 30  
The reversed list is: 30 20 10  
The modified reversed list is: 30 20 40  

Specifies a new size for a list.

void resize(size_type _Newsize);

void resize(size_type _Newsize, Type val);

Parameters

_Newsize
The new size of the list.

val
The value of the new elements to be added to the list if the new size is larger that the original size. If the value is omitted, the new elements are assigned the default value for the class.

Remarks

If the list's size is less than the requested size, _Newsize, elements are added to the list until it reaches the requested size.

If the list's size is larger than the requested size, the elements closest to the end of the list are deleted until the list reaches the size _Newsize.

If the present size of the list is the same as the requested size, no action is taken.

size reflects the current size of the list.

Example

// list_resize.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )  
{   
   using namespace std;  
   list <int> c1;  
  
   c1.push_back( 10 );  
   c1.push_back( 20 );  
   c1.push_back( 30 );  
  
   c1.resize( 4,40 );  
   cout << "The size of c1 is " << c1.size( ) << endl;  
   cout << "The value of the last element is " << c1.back( ) << endl;  
  
   c1.resize( 5 );  
   cout << "The size of c1 is now " << c1.size( ) << endl;  
   cout << "The value of the last element is now " << c1.back( ) << endl;  
  
   c1.resize( 2 );  
   cout << "The reduced size of c1 is: " << c1.size( ) << endl;  
   cout << "The value of the last element is now " << c1.back( ) << endl;  
}  

The size of c1 is 4  
The value of the last element is 40  
The size of c1 is now 5  
The value of the last element is now 0  
The reduced size of c1 is: 2  
The value of the last element is now 20  

Reverses the order in which the elements occur in a list.

void reverse();

Example

// list_reverse.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   list <int> c1;  
   list <int>::iterator c1_Iter;  
  
   c1.push_back( 10 );  
   c1.push_back( 20 );  
   c1.push_back( 30 );  
  
   cout << "c1 =";  
   for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )  
      cout << " " << *c1_Iter;  
   cout << endl;  
  
   c1.reverse( );  
   cout << "Reversed c1 =";  
   for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )  
      cout << " " << *c1_Iter;  
   cout << endl;  
}  

c1 = 10 20 30  
Reversed c1 = 30 20 10  

A type that provides a bidirectional iterator that can read or modify an element in a reversed list.

typedef std::reverse_iterator<iterator> reverse_iterator;  

Remarks

A type reverse_iterator is used to iterate through the list in reverse.

Example

See the example for rbegin.

Returns the number of elements in a list.

size_type size() const;

Return Value

The current length of the list.

Example

// list_size.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )  
{  
   using namespace std;  
   list <int> c1;  
   list <int>::size_type i;  
  
   c1.push_back( 5 );  
   i = c1.size( );  
   cout << "List length is " << i << "." << endl;  
  
   c1.push_back( 7 );  
   i = c1.size( );  
   cout << "List length is now " << i << "." << endl;  
}  

List length is 1.  
List length is now 2.  

A type that counts the number of elements in a list.

typedef typename Allocator::size_type size_type;  

Example

See the example for size.

Arranges the elements of a list in ascending order or with respect to some other user-specified order.

void sort();

template <class Traits>  
void sort(Traits comp);

Parameters

comp
The comparison operator used to order successive elements.

Remarks

The first member function puts the elements in ascending order by default.

The member template function orders the elements according to the user-specified comparison operation comp of class Traits.

Example

// list_sort.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )  
{  
   using namespace std;  
   list <int> c1;  
   list <int>::iterator c1_Iter;  
  
   c1.push_back( 20 );  
   c1.push_back( 10 );  
   c1.push_back( 30 );  
  
   cout << "Before sorting: c1 =";  
   for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )  
      cout << " " << *c1_Iter;  
   cout << endl;  
  
   c1.sort( );  
   cout << "After sorting c1 =";  
   for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )  
      cout << " " << *c1_Iter;  
   cout << endl;  
  
   c1.sort( greater<int>( ) );  
   cout << "After sorting with 'greater than' operation, c1 =";  
   for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )  
      cout << " " << *c1_Iter;  
   cout << endl;  
}  

Before sorting: c1 = 20 10 30  
After sorting c1 = 10 20 30  
After sorting with 'greater than' operation, c1 = 30 20 10  

Removes elements from a source list and inserts them into a destination list.

// insert the entire source list  
void splice(const_iterator Where, list<Type, Allocator>& Source);

void splice(const_iterator Where, list<Type, Allocator>&& Source);

 
// insert one element of the source list  
void splice(const_iterator Where, list<Type, Allocator>& Source, const_iterator Iter);

void splice(const_iterator Where, list<Type, Allocator>&& Source, const_iterator Iter);

 
// insert a range of elements from the source list  
void splice(const_iterator Where, list<Type, Allocator>& Source, const_iterator First, const_iterator Last);

    void splice(const_iterator Where, list<Type, Allocator>&& Source, const_iterator First, const_iterator Last);

Parameters

Where
The position in the destination list before which to insert.

Source
The source list that is to be inserted into the destination list.

Iter
The element to be inserted from the source list.

First
The first element in the range to be inserted from the source list.

Last
The first position beyond the last element in the range to be inserted from the source list.

Remarks

The first pair of member functions inserts all elements in the source list into the destination list before the position referred to by Where and removes all elements from the source list. ( &Source must not equal this.)

The second pair of member functions inserts the element referred to by Iter before the position in the destination list referred to by Where and removes Iter from the source list. (If Where == Iter || Where == ++Iter, no change occurs.)

The third pair of member functions inserts the range designated by [ First, Last) before the element in the destination list referred to by Where and removes that range of elements from the source list. (If &Source == this, the range [First, Last) must not include the element pointed to by Where.)

If the ranged splice inserts N elements, and &Source != this, an object of class iterator is incremented N times.

In all cases iterators, pointers, or references that refer to spliced elements remain valid and are transferred to the destination container.

Example

// list_splice.cpp  
// compile with: /EHsc /W4  
#include <list>  
#include <iostream>  
  
using namespace std;  
  
template <typename S> void print(const S& s) {  
    cout << s.size() << " elements: ";  
  
    for (const auto& p : s) {  
        cout << "(" << p << ") ";  
    }  
  
    cout << endl;  
}  
  
int main()  
{  
    list<int> c1{10,11};  
    list<int> c2{20,21,22};  
    list<int> c3{30,31};  
    list<int> c4{40,41,42,43};  
  
    list<int>::iterator where_iter;  
    list<int>::iterator first_iter;  
    list<int>::iterator last_iter;  
  
    cout << "Beginning state of lists:" << endl;  
    cout << "c1 = ";  
    print(c1);  
    cout << "c2 = ";  
    print(c2);  
    cout << "c3 = ";  
    print(c3);  
    cout << "c4 = ";  
    print(c4);  
  
    where_iter = c2.begin();  
    ++where_iter; // start at second element  
    c2.splice(where_iter, c1);  
    cout << "After splicing c1 into c2:" << endl;  
    cout << "c1 = ";  
    print(c1);  
    cout << "c2 = ";  
    print(c2);  
  
    first_iter = c3.begin();  
    c2.splice(where_iter, c3, first_iter);  
    cout << "After splicing the first element of c3 into c2:" << endl;  
    cout << "c3 = ";  
    print(c3);  
    cout << "c2 = ";  
    print(c2);  
  
    first_iter = c4.begin();  
    last_iter = c4.end();  
    // set up to get the middle elements  
    ++first_iter;  
    --last_iter;  
    c2.splice(where_iter, c4, first_iter, last_iter);  
    cout << "After splicing a range of c4 into c2:" << endl;  
    cout << "c4 = ";  
    print(c4);  
    cout << "c2 = ";  
    print(c2);  
}  
  

Beginning state of lists:c1 = 2 elements: (10) (11)c2 = 3 elements: (20) (21) (22)c3 = 2 elements: (30) (31)c4 = 4 elements: (40) (41) (42) (43)After splicing c1 into c2:c1 = 0 elements:c2 = 5 elements: (20) (10) (11) (21) (22)After splicing the first element of c3 into c2:c3 = 1 elements: (31)c2 = 6 elements: (20) (10) (11) (30) (21) (22)After splicing a range of c4 into c2:c4 = 2 elements: (40) (43)c2 = 8 elements: (20) (10) (11) (30) (41) (42) (21) (22)  

Exchanges the elements of two lists.

void swap(list<Type, Allocator>& right);

friend void swap(list<Type, Allocator>& left, list<Type, Allocator>& right)  

Parameters

right
The list providing the elements to be swapped, or the list whose elements are to be exchanged with those of the list left.

left
A list whose elements are to be exchanged with those of the list right.

Example

// list_swap.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )  
{  
   using namespace std;  
   list <int> c1, c2, c3;  
   list <int>::iterator c1_Iter;  
  
   c1.push_back( 1 );  
   c1.push_back( 2 );  
   c1.push_back( 3 );  
   c2.push_back( 10 );  
   c2.push_back( 20 );  
   c3.push_back( 100 );  
  
   cout << "The original list c1 is:";  
   for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )  
      cout << " " << *c1_Iter;  
   cout << endl;  
  
   c1.swap( c2 );  
  
   cout << "After swapping with c2, list c1 is:";  
   for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )  
      cout << " " << *c1_Iter;  
   cout << endl;  
  
   swap( c1,c3 );  
  
   cout << "After swapping with c3, list c1 is:";  
   for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )  
      cout << " " << *c1_Iter;  
   cout << endl;  
}  

The original list c1 is: 1 2 3  
After swapping with c2, list c1 is: 10 20  
After swapping with c3, list c1 is: 100  

Removes adjacent duplicate elements or adjacent elements that satisfy some other binary predicate from a list.

void unique();

template <class BinaryPredicate>  
void unique(BinaryPredicate pred);

Parameters

pred
The binary predicate used to compare successive elements.

Remarks

This function assumes that the list is sorted, so that all duplicate elements are adjacent. Duplicates that are not adjacent will not be deleted.

The first member function removes every element that compares equal to its preceding element.

The second member function removes every element that satisfies the predicate function pred when compared with its preceding element. You can use any of the binary function objects declared in the <functional>header for the argument pred or you can create your own.

Example

// list_unique.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )  
{  
   using namespace std;  
   list <int> c1;  
   list <int>::iterator c1_Iter, c2_Iter,c3_Iter;  
   not_equal_to<int> mypred;  
  
   c1.push_back( -10 );  
   c1.push_back( 10 );  
   c1.push_back( 10 );  
   c1.push_back( 20 );  
   c1.push_back( 20 );  
   c1.push_back( -10 );  
  
   cout << "The initial list is c1 =";  
   for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )  
      cout << " " << *c1_Iter;  
   cout << endl;  
  
   list <int> c2 = c1;  
   c2.unique( );  
   cout << "After removing successive duplicate elements, c2 =";  
   for ( c2_Iter = c2.begin( ); c2_Iter != c2.end( ); c2_Iter++ )  
      cout << " " << *c2_Iter;  
   cout << endl;  
  
   list <int> c3 = c2;  
   c3.unique( mypred );  
   cout << "After removing successive unequal elements, c3 =";  
   for ( c3_Iter = c3.begin( ); c3_Iter != c3.end( ); c3_Iter++ )  
      cout << " " << *c3_Iter;  
   cout << endl;  
}  

The initial list is c1 = -10 10 10 20 20 -10  
After removing successive duplicate elements, c2 = -10 10 20 -10  
After removing successive unequal elements, c3 = -10 -10  

A type that represents the data type stored in a list.

typedef typename Allocator::value_type value_type;  

Remarks

value_type is a synonym for the template parameter Type.

Example

// list_value_type.cpp  
// compile with: /EHsc  
#include <list>  
#include <iostream>  
  
int main( )   
{  
   using namespace std;  
   list<int>::value_type AnInt;  
   AnInt = 44;  
   cout << AnInt << endl;  
}  

<list>
Thread Safety in the C++ Standard Library
Standard Template Library

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