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javarecursionfactorial

50 factorial in Java Using BigInteger

So I've been trying to get big factorials like 50 using BigInteger. But when i run this program in cmd, i get unexpected error at line 16: fact=fact.multiply(new BigInteger(getFactorial(n-1))). I am not even able to see the thrown exception as it gets scrolled out. Please help me find the error.

import java.math.BigInteger;
class FactorialUsingRecursion {

public static void main(String args[]) {
    int num=50;
    String fact=getFactorial(num);
    System.out.println(num+"! = "+fact);
}

static String getFactorial(int n) {
    BigInteger fact=new BigInteger(n+"");

    if(fact.toString()=="1") {
        return "1";
    }
    fact=fact.multiply(new BigInteger(getFactorial(n-1)));//error line
    return fact.toString();
}
}
Solution

  • The problem is with String comparison in if condition. Change that if condition to the following:

    if(fact.intValue() == 1) {