#include <stdio.h>
#include <string.h>
void swap(char *x, char *y)
{
	char temp;
	temp = *x;
	*x = *y;
	*y = temp;
}
void permute(char *a, int l, int r)
{
int i;
if (l == r)
	printf("%s\n", a);
else
{
	for (i = l; i <= r; i++)
	{
		swap((a+l), (a+i));
		permute(a, l+1, r);
		swap((a+l), (a+i)); 
    }
}
}
int main()
{
	char str[100];
   scanf("%s",str);
	int n = strlen(str);
	permute(str, 0, n-1);
	return 0;
}

• Problem Description
  Consider the string Find the permutations of string ABC
• Test Case 1
  Input (stdin)ABC
  Expected OutputABC
  ACB
  BAC
  BCA
  CBA
  CAB
• Test Case 2
  Input (stdin)BHLY
  Expected OutputBHLY
  BHYL
  BLHY
  BLYH
  BYLH
  BYHL
  HBLY
  HBYL
  HLBY
  HLYB
  HYLB
  HYBL
  LHBY
  LHYB
  LBHY
  LBYH
  LYBH
  LYHB
  YHLB
  YHBL
  YLHB
  YLBH
  YBLH
  YBHL