/**
 * Example of Comparator, with rectangles.
 */

#include <stdlib.h>

#ifdef USE_DOT_H
    #include <iostream.h>
#else
    #include <iostream>
    #if !defined( __BORLANDC__ ) || __BORLANDC__ >= 0x0530
        using namespace std;      // Borland has a bug
    #endif
#endif

#ifndef SAFE_STL
    #include <vector>
    using std::vector;
#else
    #include "vector.h"
    #include "StartConv.h"
#endif


// A simple rectangle class.

class Rectangle
{
  public:
    Rectangle( int len = 0, int wid = 0 )
      : length( len ), width( wid ) { }

    int getLength( ) const
      { return length; }

    int getWidth( ) const
      { return width; }

    void print( ostream & out = cout ) const
      { out << "Rectangle " << getLength( ) << " by " << getWidth( ); }

  private:
    int length;
    int width;
};

ostream & operator<< ( ostream & out, const Rectangle & rhs )
{
    rhs.print( out );
    return out;
}


// Compare object: ordering by length.
class LessThanByLength
{
  public:
    bool operator( ) ( const Rectangle & lhs, const Rectangle & rhs ) const
      { return lhs.getLength( ) < rhs.getLength( ); }
};


// Compare object: ordering by area.
class LessThanByArea
{
  public:
    bool operator( ) ( const Rectangle & lhs, const Rectangle & rhs ) const
      { return lhs.getLength( ) * lhs.getWidth( ) <
               rhs.getLength( ) * rhs.getWidth( ); }
};

// Generic findMax, with a function object.
// Precondition: a.size( ) > 0.
template <class Object, class Comparator>
const Object & findMax( const vector<Object> & a, Comparator isLessThan )
{
    int maxIndex = 0;

    for( int i = 1; i < a.size( ); i++ )
        if( isLessThan( a[ maxIndex ], a[ i ] ) )
            maxIndex = i;

    return a[ maxIndex ];
}

// main: create four rectangles.
// find the max, two ways.
int main( )
{
    vector<Rectangle> a;

    a.push_back( Rectangle( 1, 10 ) );
    a.push_back( Rectangle( 10, 1 ) );
    a.push_back( Rectangle( 5, 5 ) );
    a.push_back( Rectangle( 4, 6 ) );

    cout << "Largest length:\n\t" << findMax( a, LessThanByLength( ) ) << endl;
    cout << "Largest area:\n\t" << findMax( a, LessThanByArea( ) ) << endl;

    return 0;
}


#ifdef SAFE_STL
    #include "EndConv.h"
#endif