There is a Java program that is missing one recursive function:
public class Factorial { /* / 1 when n is 0; * fact(n) = | * \ n*fact(n-1) otherwise */ public static int fact(int n) { return 0; } /* Factorial Test Framework * * Notice the odd expected value for fact(20). It is negative because * fact(20) should be 2432902008176640000, but the maximum int is only * 2147483647. What does Java do when integers run out of range? It starts * over at -2147483648. And then things get wacky. To fix the we would need * more than just a long integer. We need an arbitrary precision type. (You * should read this as literary foreshadowing.) */ public static void main(String[] args) { int[] input = {0, 1, 2, 3, 4, 10, 20}; int[] expect = {1, 1, 2, 6, 24, 3628800, -2102132736}; boolean error = false; for(int i = 0 ; i < input.length; i++) { int answer = fact(input[i]); if(answer != expect[i]) { System.out.printf(\"ERROR: fact(%d) returned %d not %d.\n\", input[i], answer, expect[i]); error = true; } } if(error) System.exit(1); else System.out.println(\"Good Job!\"); }}
