/*factorial.c - several versions of a factorial program.  Copyright (c) 1998
  Matthew Belmonte.*/

int main()
  {
  int n;
  long factorial;
  printf("Compute the factorial of what number? ");
  scanf("%d", &n);
  factorial = 1L;
  while(n > 0)
    factorial *= n--;
  printf("The factorial is %ld\n", factorial);
  return 0;
  }

/*the same, but counting up to n instead of down to 0*/
int main()
  {
  register int count;
  int n;
  long factorial;
  printf("Compute the factorial of what number? ");
  scanf("%d", &n);
  factorial = 1L;
  count = 1;
  while(count <= n)
    factorial *= count++;
  printf("%d! = %ld\n", n, factorial);
  return 0;
  }

/*an equivalent loop using 'for' instead of 'while'*/
int main()
  {
  register int count;
  int n;
  long factorial;
  printf("Compute the factorial of what number? ");
  scanf("%d", &n);
  for(factorial = 1L, count = 1; count <= n; count++)
    factorial *= count;
  printf("%d! = %ld\n", n, factorial);
  return 0;
  }