Theoretical Computer Science

0. Write a function that returns the factorial of a number. (Solution: This is a typical, can-you-program warm-up question. Example 1 shows the iterative and recursive solutions. Notice that in both solutions, I check the input values and boundary conditions. Factorials of negative numbers are undefined, and the factorial of both 0 and 1 are 1. The functions in Example 1 handle these cases correctly, and they initialize all variables. (a) int iterative_factorial (int number) { int rval = 1; /* first check input values */ if (number < 0) { /* we'll return -1 if there's an error */ return (-1); } for (int i = number; i > 1; i--) { rval = rval * i; } return (rval); } (b) int recursive_factorial (int number) { if (number < 0) { /* we'll return -1 if there's an error */ return (-1); } else if ((number == 0) || (number == 1)) { return (1); } else { return recursive_factorial (number-1) * number; } })