operator== (map)

Tests if the map object on the left side of the operator is equal to the map object on the right side.

bool operator==( 
   const map <Key, Type, Traits, Allocator>& _Left, 
   const map <Key, Type, Traits, Allocator>& _Right 
);

_Left

An object of type map.

_Right

An object of type map.

true if the map on the left side of the operator is equal to the map on the right side of the operator; otherwise false.

The comparison between map objects is based on a pairwise comparison of their elements. Two maps are equal if they have the same number of elements and their respective elements have the same values. Otherwise, they are unequal.

// map_op_eq.cpp
// compile with: /EHsc
#include <map>
#include <iostream>

int main( )
{
   using namespace std;
   map < int, int > m1, m2, m3;
   int i;
   typedef pair < int, int > Int_Pair;

   for ( i = 0 ; i < 3 ; i++ )
   {
      m1.insert ( Int_Pair ( i, i ) );
      m2.insert ( Int_Pair ( i, i * i ) );
      m3.insert ( Int_Pair ( i, i ) );
   }

   if ( m1 == m2 )
      cout << "The maps m1 and m2 are equal." << endl;
   else
      cout << "The maps m1 and m2 are not equal." << endl;

   if ( m1 == m3 )
      cout << "The maps m1 and m3 are equal." << endl;
   else
      cout << "The maps m1 and m3 are not equal." << endl;
}
The maps m1 and m2 are not equal.
The maps m1 and m3 are equal.

Header: <map>

Namespace: std

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