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operator< (map)

 

Tests if the map object on the left side of the operator is less than 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 strictly less than 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. The less-than relationship between two objects is based on a comparison of the first pair of unequal elements.

Example

// map_op_lt.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 = 1 ; i < 3 ; i++ )
   {
      m1.insert ( Int_Pair ( i, i ) );
      m2.insert ( Int_Pair ( i, i * i ) );
      m3.insert ( Int_Pair ( i, i - 1 ) );
   }

   if ( m1 < m2 )
      cout << "The map m1 is less than the map m2." << endl;
   else
      cout << "The map m1 is not less than the map m2." << endl;

   if ( m1 < m3 )
      cout << "The map m1 is less than the map m3." << endl;
   else
      cout << "The map m1 is not less than the map m3." << endl;
}
The map m1 is less than the map m2.
The map m1 is not less than the map m3.

Requirements

Header: <map>

Namespace: std

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