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<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

<unordered_map>