本程序使用到了if else和switch语句：

  1: import java.util.Scanner;
  2: public class 猜拳 {
  3:   public static void main(String[] args) {
  4:     System.out.println("          ★★★★猜拳★★★★");
  5:     System.out.print("请出拳（1、剪刀，2、石头，3、布）：");
  6:     Scanner in=new Scanner(System.in);
  7:     int People=in.nextInt();
  8:     int Computer=(int)(Math.random()*3)+1;
  9:     String MarkPeople="人";
 10:     String MarkComputer="电脑";
 11:     switch(People){//和以下的switch一样，为了输出什么拳头
 12:       case 1:MarkPeople="剪刀";
 13:       break;
 14:       
 15:       case 2:MarkPeople="石头";
 16:       break;
 17:       
 18:       case 3:MarkPeople="布";
 19:       break;
 20:     }
 21:     switch(Computer){
 22:       case 1:MarkComputer="剪刀";
 23:       break;
 24:       
 25:       case 2:MarkComputer="石头";
 26:       break;
 27:       
 28:       case 3:MarkComputer="布";
 29:       break;    
 30:     }
 31: //以下if（黄色部分）是出拳算法
 32:     if(People==Computer){
 33:       System.out.println("\n☆平局☆\n"+"  你出的是："+MarkPeople+"，电脑出的是："+MarkComputer);
 34:     }
 35:     else if(People==1&&Computer==3||People==2&&Computer==1||People==3&&Computer==2){
 36:       System.out.println("\n☆你赢了☆\n"+"  你出的是："+MarkPeople+"，电脑出的是："+MarkComputer);
 37:     }else{
 38:       System.out.println("\n☆你输了☆\n"+"  你出的是："+MarkPeople+"，电脑出的是："+MarkComputer);
 39:     }
 40:   }
 41: }

黄色部分为出拳的比较！从“人”的出拳输赢及平局来做三个if！