Factorial in Java

Question

I\'ve been using this factorial program for Java:

public static long factorial(int a) {

    if(a<1) {
        return 1;
    }
    long result=1;
    long         


        

Answer 1

Overflow (and underflow) is silent according to the JLS, which is why your result was a "surprise".

You have two choices:

• if an exact answer is required, use BigInteger
• if exactness is not required, use double (although even that will overflow past 170!)