java 代码 求大师解

MyRandom rnd = new MyRandom();
    Card c1 = cards[rnd.nextInt(cards.length)-1];
    Card c2 = cards[rnd.nextInt(cards.length)-1];
    
    System.out.println("Two cards are drawn:");
    System.out.println("c1 = " + c1 + " and c2 = " + c2);

    // compare c1 and c2
    if (c1.compareTo(c2) < 0) {
      System.out.println(c1 + " is smaller than " + c2);
    }
    else if (c1.compareTo(c2) == 0) { 
      System.out.println(c1 + " is the same as " + c2); 
    }
    else {
      System.out.println(c1 + " is larger than " + c2);
    }
  }
}

这个compare to 应该怎么写？ 

    public int compareTo(Card c) {

public class Card {
	char cardNumber;

	public Card(char chr) {
		// TODO Auto-generated constructor stub
		this.cardNumber = chr;
	}

	public int compareTo(Card c) {
		int out = 0;
		if ((byte) this.cardNumber < (byte) c.cardNumber) {
			out = -1;
		}
		if ((byte) this.cardNumber > (byte) c.cardNumber) {
			out = 1;
		}
		return out;

	}

}

import java.util.Random;

public class MyRandom {
	public int nextInt(int max) {
		Random r = new Random();

		return Math.abs(r.nextInt(max) % max + 1);

	}

}


public class CardTest {
	public static void main(String[] args) {

		MyRandom rnd = new MyRandom();

		Card[] cards = { new Card('1'), new Card('2') };
		System.out.println(rnd.nextInt(cards.length) - 1);
		Card c1 = cards[rnd.nextInt(cards.length) - 1];
		Card c2 = cards[rnd.nextInt(cards.length) - 1];

		System.out.println("Two cards are drawn:");
		System.out.println("c1 = " + c1 + " and c2 = " + c2);

		// compare c1 and c2
		if (c1.compareTo(c2) < 0) {
			System.out.println(c1 + " is smaller than " + c2);
		} else if (c1.compareTo(c2) == 0) {
			System.out.println(c1 + " is the same as " + c2);
		} else {
			System.out.println(c1 + " is larger than " + c2);
		}
	}

}