Project Euler – Problem 20

Problem 20: Find the sum of the digits in the number 100!

Reused my UnsignedBigInt from Problem 16

class runner
	public static void main (String[] args) throws java.lang.Exception{
		long time = System.currentTimeMillis();

		UnsignedBigInteger num = new UnsignedBigInteger(1);
		for(int i = 100; i>0; i--){
			num.multiply(i);
		}
 
		double sum = 0;
		for(int i = 0; i< num.length(); i++){
			sum += num.get(i);
		}
		System.out.println(sum);
		System.out.println("time: "+(System.currentTimeMillis() - time));
	}
}