operator!= (unordered_map)

  • Article

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

Requirements

Header: <unordered_map>

Namespace: std

See Also

Reference

Standard Template Library