text: #include <stdio.h>
  int main() {
          char a[] = "4321";  //array
             int i, j;
             int f=24; 	    //factorial
             char c;          //buffer
            while (f--) {
            printf("%s\n", a);
            i=1;
            while(a[i] > a[i-1]) i++;
            j=0;
            while(a[j] < a[i])j++;
        c=a[j];
        a[j]=a[i];
        a[i]=c;
  i--;
  for (j = 0; j < i; i--, j++) {
    c = a[i];
    a[i] = a[j];
    a[j] = c;
        }
     }
  }
  