chapter11-7.cpp

C++STL程序员开发指南

//文件名:CHAPTER11-7.cpp
#include <vector>
#include <list>
#include <algorithm>
#include <iostream>
// Return whether second element is twice the first
bool twice (int elem1, int elem2 )
{   return 2 * elem1 == elem2;  }
int main( ) 
{
   using namespace std;
   vector <int> v1, v2;
   list <int> L1;
   vector <int>::iterator Iter1, Iter2;
   list <int>::iterator L1_Iter, L1_inIter;
   int i;
   for ( i = 0 ; i <= 5 ; i++ ) { v1.push_back( 5 * i );   }
   for ( i = 0 ; i <= 5 ; i++ ) { v1.push_back( 5 * i );   }
   int ii;
   for ( ii = 4 ; ii <= 5 ; ii++ ) { L1.push_back( 5 * ii );   }
   int iii;
   for ( iii = 2 ; iii <= 4 ; iii++ )  { v2.push_back( 10 * iii );   }
   cout << "Vector v1 = ( " ;
   for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ ) cout << *Iter1 << " ";
   cout << ")" << endl;
   cout << "List L1 = ( " ;
   for ( L1_Iter = L1.begin( ) ; L1_Iter!= L1.end( ) ; L1_Iter++ ) cout << *L1_Iter << " ";
   cout << ")" << endl;
   cout << "Vector v2 = ( " ;
   for ( Iter2 = v2.begin( ) ; Iter2 != v2.end( ) ; Iter2++ ) cout << *Iter2 << " ";
   cout << ")" << endl;
   // Searching v1 for first match to L1 under identity
   vector <int>::iterator result1;
   result1 = search (v1.begin( ), v1.end( ), L1.begin( ), L1.end( ) );
   if ( result1 == v1.end( ) )
      cout << "There is no match of L1 in v1."<< endl;
   else
      cout << "There is at least one match of L1 in v1"
           << "\n and the first one begins at "<< "position "<< result1 - v1.begin( ) << "." << endl;
   // Searching v1 for a match to L1 under the binary predicate twice
   vector <int>::iterator result2;
   result2 = search  (v1.begin( ), v1.end( ), v2.begin( ), v2.end( ), twice );
   if ( result2 == v1.end( ) )
      cout << "There is no match of L1 in v1."<< endl;
   else
      cout << "There is a sequence of elements in v1 that are equivalent to those in v2"
<<"under the binary predicate twice and the first one begins at position "
           << result2 - v1.begin( ) << "." << endl;
}