chapter11-25.cpp

C++STL程序员开发指南

//文件名:CHAPTER11-25.cpp
#include <vector>
#include <set>
#include <algorithm>
#include <iostream>
#include <ostream>
using namespace std;
class CInt;
ostream& operator<<( ostream& osIn, const CInt& rhs );
#define max(a,b) (a>b)?a:b;
#define min(a,b) (a<b)?a:b;
class CInt
{
public:
   CInt( int n = 0 ) : m_nVal( n ){}
   CInt( const CInt& rhs ) : m_nVal( rhs.m_nVal ){}
   CInt&   operator=( const CInt& rhs ) {m_nVal = 
   rhs.m_nVal; return *this;}
   bool operator<( const CInt& rhs ) const 
      {return ( m_nVal < rhs.m_nVal );}
   friend ostream& operator<<( ostream& osIn, const CInt& rhs );
private:
   int m_nVal;
};
inline ostream& operator<<( ostream& osIn, const CInt& rhs )
{
   osIn << "CInt( " << rhs.m_nVal << " )"; 
   return osIn;
}
// Return whether modulus of elem1 is greater than modulus of elem2
bool mod_greater ( int elem1, int elem2 )
{
   if ( elem1 < 0 ) 
      elem1 = - elem1;
   if ( elem2 < 0 ) 
      elem2 = - elem2;
   return elem1 > elem2;
};
int main( )
{
   // Comparing integers directly using the max algorithm
   int a = 6, b = -7, c = 7;
   const int& result1 = max ( a, b, mod_greater );
   const int& result2 = max ( b, c );
   cout << "The mod_greater of the integers 6 & -7 is: "<< result1 << "." << endl;
   cout << "The larger of the integers -7 & 7 is: "<< result2 << "." << endl;
   cout << endl;
   // Comparing set containers with elements of type CInt using the max algorithm
   CInt c1 = 1, c2 = 2, c3 = 3;
   set<CInt> s1, s2, s3;
   set<CInt>::iterator s1_Iter, s2_Iter, s3_Iter;
   s1.insert ( c1 );
   s1.insert ( c2 );
   s2.insert ( c2 );
   s2.insert ( c3 );
   cout << "s1 = (";
   for ( s1_Iter = s1.begin( ); s1_Iter != --s1.end( ); s1_Iter++ )
      cout << " " << *s1_Iter << ",";
   s1_Iter = --s1.end( );
   cout << " " << *s1_Iter << " )." << endl;
   cout << "s2 = (";
   for ( s2_Iter = s2.begin( ); s2_Iter != --s2.end( ); s2_Iter++ )
      cout << " " << *s2_Iter << ",";
   s2_Iter = --s2.end( );
   cout << " " << *s2_Iter << " )." << endl;
   s3 = max ( s1, s2 );
   cout << "s3 = max ( s1, s2 ) = (";
   for ( s3_Iter = s3.begin( ); s3_Iter != --s3.end( ); s3_Iter++ )
      cout << " " << *s3_Iter << ",";
   s3_Iter = --s3.end( );
   cout << " " << *s3_Iter << " )." << endl << endl;
s3 = min ( s1, s2 );
   cout << "s3 = min ( s1, s2 ) = (";
   for ( s3_Iter = s3.begin( ); s3_Iter != --s3.end( ); s3_Iter++ )
      cout << " " << *s3_Iter << ",";
   s3_Iter = --s3.end( );
   cout << " " << *s3_Iter << " )." << endl << endl;
   // Comparing vectors with integer elements using the max algorithm
   vector <int> v1, v2, v3, v4, v5;
   vector <int>::iterator Iter1, Iter2, Iter3, Iter4, Iter5;
   int i;
   for ( i = 0 ; i <= 2 ; i++ )   {      v1.push_back( i );   }
   int ii;
   for ( ii = 0 ; ii <= 2 ; ii++ )   {      v2.push_back( ii );   }
   int iii;
   for ( iii = 0 ; iii <= 2 ; iii++ )   {      v3.push_back( 2 * iii );   }
   cout << "Vector v1 is ( " ;
   for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )    cout << *Iter1 << " ";
   cout << ")." << endl;
   cout << "Vector v2 is ( " ;
   for ( Iter2 = v2.begin( ) ; Iter2 != v2.end( ) ; Iter2++ )    cout << *Iter2 << " ";
   cout << ")." << endl;
   cout << "Vector v3 is ( " ;
   for ( Iter3 = v3.begin( ) ; Iter3 != v3.end( ) ; Iter3++ )    cout << *Iter3 << " ";
   cout << ")." << endl;
   v4 = max ( v1, v3 );
   v5 = max ( v1, v3 );
   cout << "Vector v4 = max (v1,v3) is ( " ;
   for ( Iter4 = v4.begin( ) ; Iter4 != v4.end( ) ; Iter4++ )    cout << *Iter4 << " ";
   cout << ")." << endl;
   cout << "Vector v5 = min(v1,v3) is ( " ;
   for ( Iter5 = v5.begin( ) ; Iter5 != v5.end( ) ; Iter5++ )    cout << *Iter5 << " ";
   cout << ")." << endl;
}