今天我们来编写一款猜拳小游戏
分析：要求键入剪刀，石头，布，用数字分别代表剪刀，石头，布。
java中有一个Math.random();可以生成【0，1）之间的随机数，所以说这里用1，2，3代表剪刀，石头，布。 而电脑随机生成其中一个数字与用户输入的数字比较，当输入错误的时候会提示输入错误，请重新输入。
每次猜拳有三种可能性，如果电脑赢，电脑积分+10，人的积分不变；
如果人赢，人积分+10，电脑积分不变；
如果打成平手，积分不变。
需要分别定义两个变量接收积分的变化。
最后要将这两个变量的值做比较。
import java.util.Scanner;
public class Problem8 {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
System.out.println("欢迎来到猜拳小游戏");
System.out.println("======================================");
System.out.print("请输入游戏回合数：");
int num = scan.nextInt();
int scoreHuman = 0;
int scoreComputer = 0;
int i = 1;
for (; i <= num; i++) {
// System.out.println("======================================");
// System.out.println("第" + i + "回合，你的积分：" + scoreHuman + ",电脑的积分："
// + scoreComputer);
//
// System.out.println("======================================");
// System.out.print("出拳（1：剪刀，2：石头，3：布）：");
humanFightWithComputer(i, scoreHuman, scoreComputer);// 代替上部分代码功能
while (num > 0) {
int outFist = scan.nextInt();
int computerOutFist = (int) (Math.random() * 3 + 1);
if (outFist == 1 || outFist == 2 || outFist == 3) {
if (computerOutFist == 1 && outFist == 1) {
System.out.println("你：剪刀");
System.out.println("电脑：剪刀");
System.out.println("平均，积分不变");
scoreHuman += 0;
scoreComputer += 0;
break;
} else if (computerOutFist == 2 && outFist == 1) {
System.out.println("你：剪刀");
System.out.println("电脑：石头");
System.out.println("电脑赢，积分+10");
scoreHuman += 0;
scoreComputer += 10;
break;
} else if (computerOutFist == 3 && outFist == 1) {
System.out.println("你：剪刀");
System.out.println("电脑：布");
System.out.println("你赢，积分+10");
scoreHuman += 10;
scoreComputer += 0;
break;
} else if (computerOutFist == 1 && outFist == 2) {
System.out.println("你：石头");
System.out.println("电脑：剪刀");
System.out.println("你赢，积分+10");
scoreHuman += 10;
scoreComputer += 0;
break;
} else if (computerOutFist == 2 && outFist == 2) {
System.out.println("你：石头");
System.out.println("电脑：石头");
System.out.println("平局，积分不变");
scoreHuman += 0;
scoreComputer += 0;
break;
} else if (computerOutFist == 3 && outFist == 2) {
System.out.println("你：石头");
System.out.println("电脑：布");
System.out.println("电脑赢，积分+10");
scoreHuman += 0;
scoreComputer += 10;
break;
} else if (computerOutFist == 1 && outFist == 3) {
System.out.println("你：布");
System.out.println("电脑：剪刀");
System.out.println("电脑赢，积分+10");
scoreHuman += 0;
scoreComputer += 10;
break;
} else if (computerOutFist == 2 && outFist == 3) {
System.out.println("你：布");
System.out.println("电脑：石头");
System.out.println("你赢，积分+10");
scoreHuman += 10;
scoreComputer += 0;
break;
} else if (computerOutFist == 3 && outFist == 3) {
System.out.println("你：布");
System.out.println("电脑：布");
System.out.println("平局，积分不变");
scoreHuman += 0;
scoreComputer += 0;
break;
}
break;
} else {
System.out.println("出拳错误，请重新出拳");
}
}
// if(scoreHuman>scoreComputer){
// System.out.println("======================================");
// System.out.println("大获全胜！你的积分："+scoreHuman+"，电脑积分："+scoreComputer);
// System.out.println("======================================");
//
// }else if(scoreHuman==scoreComputer){
// System.out.println("======================================");
// System.out.println("棋逢对手！你的积分："+scoreHuman+"，电脑积分："+scoreComputer);
// System.out.println("======================================");
// }else{
// System.out.println("======================================");
// System.out.println("不幸败北！你的积分："+scoreHuman+"，电脑积分："+scoreComputer);
// System.out.println("======================================");
// }
}
whoWin(scoreHuman, scoreComputer);//代替上部分代码功能
}
public static void humanFightWithComputer(int i, int scoreHuman,
int scoreComputer) {
System.out.println("======================================");
System.out.println("第" + i + "回合，你的积分：" + scoreHuman + ",电脑的积分："
+ scoreComputer);
System.out.println("======================================");
System.out.print("出拳（1：剪刀，2：石头，3：布）：");
}
public static void whoWin(int scoreHuman, int scoreComputer) {
if (scoreHuman > scoreComputer) {
System.out.println("======================================");
System.out.println("大获全胜！你的积分：" + scoreHuman + "，电脑积分："
+ scoreComputer);
System.out.println("======================================");
} else if (scoreHuman == scoreComputer) {
System.out.println("======================================");
System.out.println("棋逢对手！你的积分：" + scoreHuman + "，电脑积分："
+ scoreComputer);
System.out.println("======================================");
} else {
System.out.println("======================================");
System.out.println("不幸败北！你的积分：" + scoreHuman + "，电脑积分："
+ scoreComputer);
System.out.println("======================================");
}
}
}
来源：https://www.cnblogs.com/wcq1993/p/5902669.html