Loops.java

public class Loops {
    public int fact(int n) {
	int c = n;
	int answer = 1;

	while (c > 0) {
	    answer = answer*(c);
	    c = c - 1;
	}

	return answer;
    }
    public int fact2(int n){
	int ans = 1;
	while (n > 0) {
	    ans = ans * n;
	    n = n - 1;
	}
	return ans;
    }

    public int GCD(int a, int b){
	int t = a;
	if (a > b)
	    t = b;
	while (a%t != 0 || b%t != 0){
	    t = t - 1;
	}
	return t;
    }

    public int GCD2(int a, int b){
	int x = a;
	int y = b;
	if (a <  b){
	    x = b;
	    y = a;
	}
	while (y != 0){
	    int t = x;
	    x = y;
	    y = t%y;
	}
	return x;
    }

    public boolean isPrime(int n){
	int t = (int)(Math.sqrt(n));
	boolean b = true;
	if (n == 1)
	    return false;
	while (t > 1){
	    if (n%t == 0)
		b = false;
	    t = t - 1;
	}
	return b;
    }
}