C sorting problem

[the_prince]

This is not actually C++ it is plain C and I need some clearance about why this is not working. This is a simple sorting mechanism that I am trying to implement. here is the code of my test program:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAXNUM 5

void sort_asc(char *, char *, int n);

int main ()
{
  int a, b;
  char *f_names[MAXNUM];
  char *l_names[MAXNUM];
  char buf[80];

  for (a = 0; a < MAXNUM; a++)
    {
      printf("\nFirst Name[%d]: ", a + 1);
      scanf("%s", buf);
      f_names[a] = (char *)malloc(sizeof(char) * strlen(buf));
      strcpy(f_names[a], buf);
      printf("\tSecond Name[%d]: ", a + 1);
      scanf("%s", buf);
      l_names[a] = (char *)malloc(sizeof(char) * strlen(buf));
      strcpy(l_names[a], buf);
    }

  printf("Sorting ...\n");

  sort_asc(f_names[a], l_names[a], MAXNUM);
  
  printf("\nFinished Sorting! Displaying results:");

  for (a = 0; a < MAXNUM; a++)
    printf("\nName[%d]: %s %s\n", a + 1, f_names[a], l_names[a]);

  return 0;
}

void sort_asc(char *fn, char *ln, int n)
{
  char *temp;
  int a, b, c, len;

  for (a = 0; a <= n; a ++)
    for (b = 0; b < n; b++)
      { 
	c = strcmp((const char *)fn[b], (const char *)fn[b + 1]);
	if (c > 0)
	  {
	    temp = (char *)malloc(sizeof(char) * strlen((const char *)fn[b]));
	    strcpy(temp, (const char *)fn[b]);
	    len = strlen((const char *)fn[b + 1]);
	    fn[b] = (char *)realloc(fn[b], sizeof(char) * len);
	    strcpy(fn[b], fn[b + 1]);
	    fn[b + 1] = (char *)realloc(fn[b + 1], sizeof(char) * strlen((const char *)temp));
	    strcpy(fn[b + 1], (const char *)temp);
	  }
      }
}

I'm trying to shift names as I compare them. The part with the realloc is not clear to me - I am acually using the gcc compiler and I know that this is a Visual C++ forum - but I thought that you can help guys.

Thanks anyway.

The_Prince

[Gunaamirthavelu]

sort_asc(f_names[a], l_names[a], MAXNUM);

the above code f_names[a] is null nothing is there. debug the program. check ur for loop in ur main function.