<unordered_map> operators
unordered_map::operator!=
unordered_map::operator==
unordered_multimap::operator!=
unordered_multimap::operator==
operator!=
Tests whether the unordered_map object on the left side of the operator is not equal to the unordered_map object on the right side.
bool operator!=(const unordered_map <Key, Type, Hash, Pred, Allocator>& left, const unordered_map <Key, Type, Hash, Pred, Allocator>& right);
Parameters
left
An object of type unordered_map.
right
An object of type unordered_map.
Return Value
true if the unordered_maps are not equal; false if they are equal.
Remarks
The comparison between unordered_map objects is not affected by the arbitrary order in which they store their elements. Two unordered_maps are equal if they have the same number of elements and the elements in one container are a permutation of the elements in the other container. Otherwise, they are unequal.
Example
// unordered_map_op_ne.cpp
// compile by using: cl.exe /EHsc /nologo /W4 /MTd
#include <unordered_map>
#include <iostream>
#include <ios>
int main( )
{
using namespace std;
unordered_map<int, int> um1, um2, um3;
for ( int i = 0 ; i < 3 ; ++i ) {
um1.insert( make_pair( i+1, i ) );
um1.insert( make_pair( i, i ) );
um2.insert( make_pair( i, i+1 ) );
um2.insert( make_pair( i, i ) );
um3.insert( make_pair( i, i ) );
um3.insert( make_pair( i+1, i ) );
}
cout << boolalpha;
cout << "um1 != um2: " << (um1 != um2) << endl;
cout << "um1 != um3: " << (um1 != um3) << endl;
cout << "um2 != um3: " << (um2 != um3) << endl;
}
/* Output:
um1 != um2: true
um1 != um3: false
um2 != um3: true
*/
operator==
Tests whether the unordered_map object on the left side of the operator is equal to the unordered_map object on the right side.
bool operator==(const unordered_map <Key, Type, Hash, Pred, Allocator>& left, const unordered_map <Key, Type, Hash, Pred, Allocator>& right);
Parameters
left
An object of type unordered_map.
right
An object of type unordered_map.
Return Value
true if the unordered_maps are equal; false if they are not equal.
Remarks
The comparison between unordered_map objects is not affected by the arbitrary order in which they store their elements. Two unordered_maps are equal if they have the same number of elements and the elements in one container are a permutation of the elements in the other container. Otherwise, they are unequal.
Example
// unordered_map_op_eq.cpp
// compile by using: cl.exe /EHsc /nologo /W4 /MTd
#include <unordered_map>
#include <iostream>
#include <ios>
int main( )
{
using namespace std;
unordered_map<int, int> um1, um2, um3;
for ( int i = 0 ; i < 3 ; ++i ) {
um1.insert( make_pair( i+1, i ) );
um1.insert( make_pair( i, i ) );
um2.insert( make_pair( i, i+1 ) );
um2.insert( make_pair( i, i ) );
um3.insert( make_pair( i, i ) );
um3.insert( make_pair( i+1, i ) );
}
cout << boolalpha;
cout << "um1 == um2: " << (um1 == um2) << endl;
cout << "um1 == um3: " << (um1 == um3) << endl;
cout << "um2 == um3: " << (um2 == um3) << endl;
}
/* Output:
um1 == um2: false
um1 == um3: true
um2 == um3: false
*/
operator!= (multimap)
Tests whether the unordered_multimap object on the left side of the operator is not equal to the unordered_multimap object on the right side.
bool operator!=(const unordered_multimap <Key, Type, Hash, Pred, Allocator>& left, const unordered_multimap <Key, Type, Hash, Pred, Allocator>& right);
Parameters
left
An object of type unordered_multimap.
right
An object of type unordered_multimap.
Return Value
true if the unordered_multimaps are not equal; false if they are equal.
Remarks
The comparison between unordered_multimap objects is not affected by the arbitrary order in which they store their elements. Two unordered_multimaps are equal if they have the same number of elements and the elements in one container are a permutation of the elements in the other container. Otherwise, they are not equal.
Example
// unordered_multimap_op_ne.cpp
// compile by using: cl.exe /EHsc /nologo /W4 /MTd
#include <unordered_map>
#include <iostream>
#include <ios>
int main( )
{
using namespace std;
unordered_multimap<int, int> um1, um2, um3;
for ( int i = 0 ; i < 3 ; ++i ) {
um1.insert( make_pair( i, i ) );
um1.insert( make_pair( i, i ) );
um2.insert( make_pair( i, i ) );
um2.insert( make_pair( i, i ) );
um2.insert( make_pair( i, i ) );
um3.insert( make_pair( i, i ) );
um3.insert( make_pair( i, i ) );
}
cout << boolalpha;
cout << "um1 != um2: " << (um1 != um2) << endl;
cout << "um1 != um3: " << (um1 != um3) << endl;
cout << "um2 != um3: " << (um2 != um3) << endl;
}
/* Output:
um1 != um2: true
um1 != um3: false
um2 != um3: true
*/
operator== (multimap)
Tests whether the unordered_multimap object on the left side of the operator is equal to the unordered_multimap object on the right side.
bool operator==(const unordered_multimap <Key, Type, Hash, Pred, Allocator>& left, const unordered_multimap <Key, Type, Hash, Pred, Allocator>& right);
Parameters
left
An object of type unordered_multimap.
right
An object of type unordered_multimap.
Return Value
true if the unordered_multimaps are equal; false if they are not equal.
Remarks
The comparison between unordered_multimap objects is not affected by the arbitrary order in which they store their elements. Two unordered_multimaps are equal if they have the same number of elements and the elements in one container are a permutation of the elements in the other container. Otherwise, they are unequal.
Example
// unordered_multimap_op_eq.cpp
// compile by using: cl.exe /EHsc /nologo /W4 /MTd
#include <unordered_map>
#include <iostream>
#include <ios>
int main( )
{
using namespace std;
unordered_multimap<int, int> um1, um2, um3;
for ( int i = 0 ; i < 3 ; ++i ) {
um1.insert( make_pair( i, i ) );
um1.insert( make_pair( i, i ) );
um2.insert( make_pair( i, i ) );
um2.insert( make_pair( i, i ) );
um2.insert( make_pair( i, i ) );
um3.insert( make_pair( i, i ) );
um3.insert( make_pair( i, i ) );
}
cout << boolalpha;
cout << "um1 == um2: " << (um1 == um2) << endl;
cout << "um1 == um3: " << (um1 == um3) << endl;
cout << "um2 == um3: " << (um2 == um3) << endl;
}
/* Output:
um1 == um2: false
um1 == um3: true
um2 == um3: false
*/
See also
Feedback
Coming soon: Throughout 2024 we will be phasing out GitHub Issues as the feedback mechanism for content and replacing it with a new feedback system. For more information see: https://aka.ms/ContentUserFeedback.
Submit and view feedback for