chapter10-32.cpp

C++STL程序员开发指南

//文件名:CHAPTER10-32.cpp
#include <map>
#include <iostream.h>
#if _MSC_VER > 1020   // if VC++ version is > 4.2
   using namespace std;  // std c++ libs implemented in std
#endif
void main( )
{
   multimap <int, int> m1;
   multimap <int, int> :: const_iterator m1_AcIter, m1_RcIter;
   typedef pair <int, int> Int_Pair;
   m1.insert ( Int_Pair ( 1, 10 ) );
   m1.insert ( Int_Pair ( 2, 20 ) );
   m1.insert ( Int_Pair ( 3, 20 ) );
   m1.insert ( Int_Pair ( 3, 30 ) );
   m1_RcIter = m1.lower_bound( 2 );
   cout << "The element of multimap m1 with a key of 2 is: 20." << endl;
   m1_RcIter = m1.lower_bound( 3 );
   cout << "The first element of multimap m1 with a key of 3 is: "<< m1_RcIter -> second << "." << endl;
   // If no match is found for the key, end( ) is returned
   m1_RcIter = m1.lower_bound( 4 );
   if ( m1_RcIter == m1.end( ) )
      cout << "The multimap m1 doesn't have an element "<< "with a key of 4." << endl;
   else
      cout << "The element of multimap m1 with a key of 4 is: "<< m1_RcIter -> second << "." << endl;
   // The element at a specific location in the multimap can be
   // found using a dereferenced iterator addressing the location
   m1_AcIter = m1.end( );
   m1_AcIter--;
   m1_RcIter = m1.lower_bound( m1_AcIter -> first );
   cout << "The first element of m1 with a key matching\n"
        << "that of the last element is: "<< m1_RcIter -> second << "." << endl;
   // Note that the first element with a key equal to the key of the last element is not the last element
   if ( m1_RcIter == --m1.end( ) )
      cout << "This is the last element of multimap m1."<< endl;
   else
      cout << "This is not the last element of multimap m1."<< endl;
}