随机抽取一张牌（一副牌52张）

import java.util.*;
import javax.swing.*;  
  class Main {
    public static void main(String[] args){
      int cardNumber = (int)(Math.random() * 100) % 13;
      int cardFlower = (int)(Math.random() * 10) % 4;
      String cardNumberString = "";
      String cardFlowerString = "";
      
      switch(cardNumber){
        case 0:
          cardNumberString = "Ace";
          break;
        case 1:
          cardNumberString = "2";
          break;
        case 2:
          cardNumberString = "3";
          break;
        case 3:
          cardNumberString = "4";
          break;
        case 4:
          cardNumberString = "5";
          break;
        case 5:
          cardNumberString = "6";
          break;
        case 6:
          cardNumberString = "7";
          break;
        case 7:
          cardNumberString = "8";
          break;
        case 8:
          cardNumberString = "9";
          break;
        case 9:
          cardNumberString = "10";
          break;
        case 10:
          cardNumberString = "Jack";
          break;
        case 11:
          cardNumberString = "Queen";
          break;
        case 12:
          cardNumberString = "King";
          break;
     }
      switch(cardFlower){
        case 0:
          cardFlowerString = "Clubs";
          break;
        case 1:
          cardFlowerString = "Diamond";
        case 2:
          cardFlowerString = "Heart";
          break;
        case 3:
          cardFlowerString = "Spades";
     }
      System.out.print("The card you picked is " + cardNumberString + " of " + cardFlowerString);
    }
  }