// C program to print all permutations with duplicates allowed
#include <stdio.h>
#include <string.h>
#define OK 1
#define KO 0
/* Function to swap values at two pointers */
void swap(char *x, char *y)
{
char temp;
temp = *x;
*x = *y;
*y = temp;
}
/* Function to print permutations of string
This function takes three parameters:
1. String
2. Starting index of the string
3. Ending index of the string. */
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)); //backtrack
}
}
}
/* Driver program to test above functions */
int main(int argc, char *argv[])
{
if ((argc != 2) || (strlen(argv[1]) > 10))
{
printf("Utilización: %s Cadena\n", argv[0]);
printf("'Cadena' no puede tener más de 10 caracteres.\n");
return KO;
}
char str[27];
strcpy(str, argv[1]);
int n = strlen(str);
permute(str, 0, n-1);
return OK;
}