function_pointer.cpp

/* Usage: To implement a function pointer with asc() , desc()
* Author: Allen (allen501pc@hotmail.com)
* Date: 04/26/2009
* Output:
* Sorted number list.
*/
#include <iostream>
using namespace std;

bool asc(int *,int *);
bool desc(int *,int *);

void mysort(int *,size_t,bool (*)(int *, int *));
void print(int [],size_t);
int main(int argc,char * argv[])
{
  int iarray[10]={3,4,7,9,8,2,5,1,6,10};
  mysort(iarray,10,desc); // sort by desc
  print(iarray,10);
  mysort(iarray,10,asc); // sort by asc
  print(iarray,10);
}

bool asc(int * a,int * b)
{
  int temp_int;
  if(*a>*b)
  {
      temp_int=*a;
      *a=*b;
      *b=temp_int;
      return true;
  }
  return false;
}

bool desc(int * a,int * b)
{
  int temp_int;
  if(*a<*b)
  {
      temp_int=*a;
      *a=*b;
      *b=temp_int;
      return true;
  }
  return false;
}


void mysort(int * iarray,size_t size,bool (*func)(int *,int *))
{
  size_t i;
  bool swapped;
  do
  {
      swapped=false;
      for(i=0;i<size-1;i++)
      {
          if((*func)(&iarray[i],&iarray[i+1]))
              swapped=true;
      }
  }while(swapped);
}

void print(int * iarray,size_t size)
{
  size_t i;
  cout << "The array cotent is..." << endl;
  for(i=0;i<size;i++)
  {
      cout << "array[" << i+1 << "] = " << iarray[i] << endl;
  }
}