String Permutations

[mrkrinkle]

Hi, I was doing some practice problems and one of them is to find all the different string permutations of ABC.

Here is my code which gives no errors or warnings but clearly my logic is wrong somewhere and I cannot find where.

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

void swap(char *a, char *b){
char temp;

temp = *a;
*a = *b;
*b = temp;
}




void permute( char *str, int i, int n){

int j, range = n - i;

 if (i == n)
     printf("%s\n", str);
 else{

      for( j = i; j <= range; j++){
      swap(&str[i],&str[n]);
      permute(str, i, j);
      swap(&str[i],&str[n]);}
}
}

int main(void){


char *ptr; 
char string[] = "ABC";

ptr = string;

permute(ptr,0,2);
return 0;}

[synhyborex]

void permute( char *str, int i, int n){

int j, range = n - i;

 if (i == n)
     printf("%s\n", str);
 else{

      for( j = i; j <= range; j++){
      swap(&str[i],&str[n]);
      permute(str, i, j);
      swap(&str[i],&str[n]);}
}
}

this might be just me, but i don't think you can call a function within its own definition?

[CommonTater]

this might be just me, but i don't think you can call a function within its own definition?

Sure you can. It's called Recursion ...

Cprogramming.com Tutorial: Recursion