set::set

Constructs a set that is empty or that is a copy of all or part of some other set.

set( );
explicit set(
    const Traits& Comp
);
set(
    const Traits& Comp,
    const Allocator& Al
);
set(
    const set& Right
);
set(
    set&& Right
);
set(
    initializer_list<Type> IList
);
set(
    initializer_list<Type> IList,
    const Compare& Comp
);
set(
    initializer_list<Type> IList,
    const Compare& Comp, 
    const Allocator& Al
);

template<class InputIterator>
    set(
        InputIterator First,
        InputIterator Last
    );
template<class InputIterator>
    set(
        InputIterator First,
        InputIterator Last,
        const Traits& Comp
    );
template<class InputIterator>
    set(
        InputIterator First,
        InputIterator Last,
        const Traits& Comp,
        const Allocator& Al
    );

Parameters

Remarks

All constructors store a type of allocator object that manages memory storage for the set and that can later be returned by calling get_allocator. The allocator parameter is often omitted in the class declarations and preprocessing macros used to substitute alternative allocators.

All constructors initialize their sets.

All constructors store a function object of type Traits that is used to establish an order among the keys of the set and that can later be returned by calling key_comp.

The first three constructors specify an empty initial set, the second specifying the type of comparison function (comp) to be used in establishing the order of the elements and the third explicitly specifying the allocator type (al) to be used. The keyword explicit suppresses certain kinds of automatic type conversion.

The fourth constructor specifies a copy of the set right.

The next three constructors use an initializer_list to specify the elements.

The next three constructors copy the range [first, last) of a set with increasing explicitness in specifying the type of comparison function of class Traits and Allocator.

The eighth constructor specifies a copy of the set by moving right.

Example

// set_set.cpp
// compile with: /EHsc
#include <set>
#include <iostream>

int main()
{
    using namespace std;

    // Create an empty set s0 of key type integer
    set <int> s0;

    // Create an empty set s1 with the key comparison
    // function of less than, then insert 4 elements
    set <int, less<int> > s1;
    s1.insert(10);
    s1.insert(20);
    s1.insert(30);
    s1.insert(40);

    // Create an empty set s2 with the key comparison
    // function of less than, then insert 2 elements
    set <int, less<int> > s2;
    s2.insert(10);
    s2.insert(20);

    // Create a set s3 with the 
    // allocator of set s1
    set <int>::allocator_type s1_Alloc;
    s1_Alloc = s1.get_allocator();
    set <int> s3(less<int>(), s1_Alloc);
    s3.insert(30);

    // Create a copy, set s4, of set s1
    set <int> s4(s1);

    // Create a set s5 by copying the range s1[_First, _Last)
    set <int>::const_iterator s1_bcIter, s1_ecIter;
    s1_bcIter = s1.begin();
    s1_ecIter = s1.begin();
    s1_ecIter++;
    s1_ecIter++;
    set <int> s5(s1_bcIter, s1_ecIter);

    // Create a set s6 by copying the range s4[_First, _Last)
    // and with the allocator of set s2
    set <int>::allocator_type s2_Alloc;
    s2_Alloc = s2.get_allocator();
    set <int> s6(s4.begin(), ++s4.begin(), less<int>(), s2_Alloc);

    cout << "s1 =";
    for (auto i : s1)
        cout << " " << i;
    cout << endl;

    cout << "s2 = " << *s2.begin() << " " << *++s2.begin() << endl;

    cout << "s3 =";
    for (auto i : s3)
        cout << " " << i;
    cout << endl;

    cout << "s4 =";
    for (auto i : s4)
        cout << " " << i;
    cout << endl;

    cout << "s5 =";
    for (auto i : s5)
        cout << " " << i;
    cout << endl;

    cout << "s6 =";
    for (auto i : s6)
        cout << " " << i;
    cout << endl;

    // Create a set by moving s5
    set<int> s7(move(s5));
    cout << "s7 =";
    for (auto i : s7)
        cout << " " << i;
    cout << endl;

    // Create a set with an initializer_list
    cout << "s8 =";
    set<int> s8{ { 1, 2, 3, 4 } };
    for (auto i : s8)
        cout << " " << i;
    cout << endl;

    cout << "s9 =";
    set<int> s9{ { 5, 6, 7, 8 }, less<int>() };
    for (auto i : s9)
        cout << " " << i;
    cout << endl;

    cout << "s10 =";
    set<int> s10{ { 10, 20, 30, 40 }, less<int>(), s9.get_allocator() };
    for (auto i : s10)
        cout << " " << i;
    cout << endl;
}

s1 = 10 20 30 40
s2 = 10 20
s3 = 30
s4 = 10 20 30 40
s5 = 10 20
s6 = 10
s7 = 10 20
s8 = 1 2 3 4
s9 = 5 6 7 8
s10 = 10 20 30 40

Requirements

Header: <set>

Namespace: std

See Also

Reference

set Class

Standard Template Library