求两个数的最大公约数（Euclid算法）

public class Euclid{
    // recursive inplementation
    public static int gcd(int p, int q){
        if(q == 0) return p;
        else 
        {
            StdOut.println( q + " " + p % q);
            return gcd(q, p % q);
        }
    }
    // non-recursive implementation
    public static int gcd2(int p, int q){
    while(q != 0){
        int temp = q;
        q = p % q;
        p = temp;
    }
    return p;
    }
    public static void main(String[] args){
        int p = Integer.parseInt(args[0]);
        int q = Integer.parseInt(args[1]);
        int d  = gcd(p, q);
        int d2 = gcd2(p,q);
        StdOut.println("gcd(" + p + ", " + q + ") = " + d);
        StdOut.println("gcd(" + p + ", " + q + ") = " + d2);
    }
}