chapter10-27.cpp

来自「C++STL程序员开发指南」· C++ 代码 · 共 30 行

//文件名:CHAPTER10-27.cpp
#include <map>
#include <iostream>
#if _MSC_VER > 1020   // if VC++ version is > 4.2
   using namespace std;  // std c++ libs implemented in std
#endif
int main( )
{
   map <int, int> m1;
   map <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, 30 ) );
   m1_RcIter = m1.find( 2 );
   cout << "The element of map m1 with a key of 2 is: "<< m1_RcIter -> second << "." << endl;
   // If no match is found for the key, end( ) is returned
   m1_RcIter = m1.find( 4 );
   if ( m1_RcIter == m1.end( ) )
      cout << "The map m1 doesn't have an element "<< "with a key of 4." << endl;
   else cout << "The element of map m1 with a key of 4 is: "<< m1_RcIter -> second << "." << endl;
   // The element at a specific location in the map can be found 
   // using a dereferenced iterator addressing the location
   m1_AcIter = m1.end( );
   m1_AcIter--;
   m1_RcIter = m1.find( m1_AcIter -> first );
   cout << "The element of m1 with a key matching "
        << "that of the last element is: "<< m1_RcIter -> second << "." << endl;
}