chapter11-23.cpp

C++STL程序员开发指南

//文件名:CHAPTER11-23.cpp
#include <vector>
#include <algorithm>
#include <functional>      //For greater<int>( )
#include <iostream>
// Return whether modulus of elem1 is less than modulus of elem2
bool mod_lesser ( int elem1, int elem2 )
{
   if ( elem1 < 0 )
      elem1 = - elem1;
   if ( elem2 < 0 )
      elem2 = - elem2;
   return elem1 < elem2;
}
int main( )
{
   using namespace std;
   vector <int> v1;
   vector <int>::iterator Iter1;
   pair < vector <int> :: iterator , vector <int> :: iterator > Result1, Result2, Result3;
   // Constructing vectors v1a & v1b with default less than ordering
   int i;
   for ( i = -1 ; i <= 4 ; i++ )
   {      v1.push_back(  i );   }
   int ii;
   for ( ii =-3 ; ii <= 0 ; ii++ )
   {      v1.push_back( ii );   }
   sort ( v1.begin ( ) , v1.end ( ) );
   cout << "Original vector v1 with range sorted by the\n "
        <<  "binary predicate less than is  v1 = ( " ;
   for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
      cout << *Iter1 << " ";
   cout << ")." << endl;
   // Constructing vectors v2 with range sorted by greater
   vector <int> v2 ( v1 );
   vector <int>::iterator Iter2;
   sort ( v2.begin ( ) , v2.end ( ) , greater<int> ( ) );
   cout << "Original vector v2 with range sorted by the\n "
        <<  "binary predicate greater is    v2 = ( " ;
   for ( Iter2 = v2.begin ( ) ; Iter2 != v2.end ( ) ; Iter2++ )
      cout << *Iter2 << " ";
   cout << ")." << endl;
   // Constructing vectors v3 with range sorted by mod_lesser
   vector <int> v3 ( v1 );
   vector <int>::iterator Iter3;
   sort ( v3.begin ( ) , v3.end ( ) , mod_lesser );
   cout << "Original vector v3 with range sorted by the\n "
        << "binary predicate mod_lesser is v3 = ( " ;
   for ( Iter3 = v3.begin ( ) ; Iter3 != v3.end ( ) ; Iter3++ )
      cout << *Iter3 << " ";
   cout << ")." << endl << endl;
   // equal_range of 3 in v1 with default binary predicate less <int> ( )
   Result1 = equal_range ( v1.begin ( ) , v1.end ( ) , 3 );
   cout << "The lower_bound in v1 for the element with a value of 3 is: "
        << *Result1.first << "." << endl;
   cout << "The upper_bound in v1 for the element with a value of 3 is: "
        << *Result1.second << "." << endl;
   cout << "The equivalence class for the element with a value of 3 in"
        << "\n v1 includes the elements: ( ";
   for ( Iter1 = Result1.first ; Iter1 != Result1.second ; Iter1++ )
      cout << *Iter1 << " ";
   cout << ")." << endl << endl;
   // equal_range of 3 in v2 with the binary predicate greater <int> ( )
   Result2 = equal_range ( v2.begin ( ) , v2.end ( ) , 3 , greater <int> ( ) );
   cout << "The lower_bound in v2 for the element with a value of 3 is: "
        << *Result2.first << "." << endl;
   cout << "The upper_bound in v2 for the element with a value of 3 is: "
        << *Result2.second << "." << endl;
   cout << "The equivalence class for the element with a value of 3 in"
        << "\n v2 includes the elements: ( ";
   for ( Iter2 = Result2.first ; Iter2 != Result2.second ; Iter2++ )
      cout << *Iter2 << " ";
   cout << ")." << endl << endl;
   // equal_range of 3 in v3 with the binary predicate mod_lesser
   Result3 = equal_range ( v3.begin ( ) , v3.end ( ) , 3 ,mod_lesser );
   cout << "The lower_bound in v3 for the element with a value of 3 is: "
        << *Result3.first << "." << endl;
   cout << "The upper_bound in v3 for the element with a value of 3 is: "
        << *Result3.second << "." << endl;
   cout << "The equivalence class for the element with a value of 3 in"
        << "\n v3 includes the elements: ( ";
   for ( Iter3 = Result3.first ; Iter3 != Result3.second ; Iter3++ )
      cout << *Iter3 << " ";
   cout << ")." << endl << endl;
}