#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
  Given numbers 1,2,3. Write a C Program to Generate All Permutations of the given numbers using BackTracking.
• Test Case 1
  Input (stdin)123
  Expected Output123
  132
  213
  231
  321
  312
• Test Case 2
  Input (stdin)9385
  Expected Output9385
  9358
  9835
  9853
  9583
  9538
  3985
  3958
  3895
  3859
  3589
  3598
  8395
  8359
  8935
  8953
  8593
  8539
  5389
  5398
  5839
  5893
  5983
  5938