map::erase

iterator erase(
   iterator _Where
);
iterator erase(
   iterator _First,
   iterator _Last
);
size_type erase(
   const key_type& _Key
);

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

int main( )
{
   using namespace std;
   map <int, int> m1, m2, m3;
   map <int, int> :: iterator pIter, Iter1, Iter2;
   int i, n;
   typedef pair <int, int> Int_Pair;

   for ( i = 1 ; i < 5 ; i++ )
   {
      m1.insert ( Int_Pair ( i, i ) );
      m2.insert ( Int_Pair ( i, i*i ) );
      m3.insert ( Int_Pair ( i, i-1 ) );
   }

   // The 1st member function removes an element at a given position
   Iter1 = ++m1.begin( );
   m1.erase( Iter1 );

   cout << "After the 2nd element is deleted, the map m1 is:" ;
   for ( pIter = m1.begin( ) ; pIter != m1.end( ) ; pIter++ )
      cout << " " << pIter -> second;
   cout << "." << endl;

   // The 2nd member function removes elements
   // in the range [_First, _Last)
   Iter1 = ++m2.begin( );
   Iter2 = --m2.end( );
   m2.erase( Iter1, Iter2 );

   cout << "After the middle two elements are deleted,"
        << " the map m2 is:" ;
   for ( pIter = m2.begin( ) ; pIter != m2.end( ) ; pIter++ )
      cout << " " << pIter -> second;
   cout << "." << endl;

   // The 3rd member function removes elements with a given _Key
   n = m3.erase( 2 );

   cout << "After the element with a key of 2 is deleted,\n"
        << "the map m3 is:" ;
   for ( pIter = m3.begin( ) ; pIter != m3.end( ) ; pIter++ )
      cout << " " << pIter -> second;
   cout << "." << endl;

   // The 3rd member function returns the number of elements removed
   cout << "The number of elements removed from m3 is: "
        << n << "." << endl;

   // The dereferenced iterator can also be used to specify a key
   Iter1 = ++m3.begin( );
   m3.erase( Iter1 );

   cout << "After another element with a key equal to that"
        << endl;
   cout  << "of the 2nd element is deleted, "
         << "the map m3 is:" ;
   for ( pIter = m3.begin( ) ; pIter != m3.end( ) ; pIter++ )
      cout << " " << pIter -> second;
   cout << "." << endl;
}

After the 2nd element is deleted, the map m1 is: 1 3 4.
After the middle two elements are deleted, the map m2 is: 1 16.
After the element with a key of 2 is deleted,
the map m3 is: 0 2 3.
The number of elements removed from m3 is: 1.
After another element with a key equal to that