分析程序

liaobenxian

请大哥大姐们帮忙分析一下程序中void quicksort( int * const, int, int );函数的定义．谢谢！

#include <iostream>
using std::cout;
using std::endl;
#include <iomanip>
using std::setw;
#include <cstdlib>
using std::rand;
using std::srand;
#include <ctime>
using std::time;
const int SIZE = 10;
const int MAX_NUMBER = 1000;

void quicksort( int * const, int, int );
void swap( int * const, int * const );
int main()
{
   int arrayToBeSorted[ SIZE ] = { 0 };
   int loop;
   srand( time( 0 ) );
   
   for ( loop = 0; loop < SIZE; loop++ )
      arrayToBeSorted[ loop ] = rand() % MAX_NUMBER;
   cout << "Initial array values are:\n";
   
  
   for ( loop = 0; loop < SIZE; loop++ )
       cout << setw( 4 ) << arrayToBeSorted[ loop ];
   cout << "\n\n";
   
   if ( SIZE == 1 )
      cout << "Array is sorted: " << arrayToBeSorted[ 0 ] << '\n';
   else
   {
      quicksort( arrayToBeSorted, 0, SIZE - 1 );
      cout << "The sorted array values are:\n";
      for ( loop = 0; loop < SIZE; loop++ )
         cout << setw( 4 ) << arrayToBeSorted[ loop ];
      cout << endl;
   }
   return 0;
}

void quicksort( int * const array, int first, int last )
{
   int partition( int * const, int, int );
   int currentLocation;
   if ( first >= last )
      return;
   currentLocation = partition( array, first, last );
   quicksort( array, first, currentLocation - 1 );
   quicksort( array, currentLocation + 1, last );
}

int partition( int * const array, int left, int right )
{
   int position = left;
  
   while ( true )
   {
      while ( array[ position ] <= array[ right ] && position != right )
         right--;
      if ( position == right )
         return position;
      if ( array[ position ] > array[ right ])
      {
         swap( &array[ position ], &array[ right ] );
         position = right;
      }
      while ( array[ left ] <= array[ position ] && left != position )
         left++;
      if ( position == left )
         return position;
      if ( array[ left ] > array[ position ] )
      {
         swap( &array[ position ], &array[ left ] );
         position = left;
      }
   }
}

void swap( int * const ptr1, int * const ptr2 )
{
   int temp;
   temp = *ptr1;
   *ptr1 = *ptr2;
   *ptr2 = temp;
}

iptton

找本说排序的书自已看看吧
给点耐心就能看明白了