如何实现石头剪刀布的Java游戏？
如何实现石头剪刀布的Java游戏？
提问于 2018-10-29 00:58:26
我的任务是编写一个程序，让用户可以在计算机上玩Rock，Paper，Scissors游戏。
说明：
主方法应该有两个嵌套循环，其中外循环将允许用户根据需要经常玩游戏，并且只要存在平局，内循环将玩游戏。在userChoice（）方法的while循环中调用方法isValidChoice（），以验证用户输入的选项必须是“rock”，“paper”或“scissors”。如果输入了无效字符串，则isValidChoice（）将返回false，并且程序应该请求新输入，直到给出有效输入。
情况：
当用户输入有效输入时，程序运行正常。但是，一旦它不是有效的输入，就会出现一个小问题。
结果：
Enter rock, paper, or scissors: rocky
Invalid input, enter rock, paper, or scissors: roc
Invalid input, enter rock, paper, or scissors: rock
The computer's choice was paper
The user's choice was rocky
Play again? (y/n)
如您所见，程序识别无效输入。用户最后第三次输入有效输入。但是，它显示用户的第一个选择“rocky”无效。因此程序无法显示谁获胜。
题
我需要你的帮助。 我希望我的程序运行如下： 当用户输入多个无效输入时，但一旦输入有效输入，我的程序仍应能够显示用户的有效输入并显示获胜者。
import java.util.Scanner;
import java.util.Random;
public class RockPaperScissorsGame
{
public static void main (String[] args)
{
Scanner keyboard = new Scanner(System.in);
String computer, user;
char keepPlaying;
do
{
computer = computerChoice();
user = userChoice();
System.out.println("The computer's choice was " + computer);
System.out.println("The user's choice was " + user);
determineWinner(computer, user);
while (computer.equals(user))
{
computer = computerChoice();
user = userChoice();
System.out.println("The computer's choice was " + computer);
System.out.println("The user's choice was " + user);
determineWinner(computer, user);
}
System.out.println("\n" + "Play again? (y/n)");
keepPlaying = keyboard.nextLine().toLowerCase().charAt(0);
while ( keepPlaying != 'y' && keepPlaying != 'n' )
{
System.out.println("Invalid input, please enter (y/n)");
keepPlaying = keyboard.nextLine().toLowerCase().charAt(0);
}
} while (keepPlaying == 'y');
}
public static String computerChoice()
{
String[] choice = {"rock","paper","scissors"};
Random rand = new Random();
int computerChoice = rand.nextInt(3);
return choice[computerChoice];
}
public static String userChoice()
{
Scanner keyboard = new Scanner(System.in);
System.out.print("Enter rock, paper, or scissors: ");
String choice = keyboard.nextLine();
isValidChoice(choice);
return choice;
}
public static boolean isValidChoice (String choice)
{
Scanner keyboard = new Scanner(System.in);
while (!(choice.equalsIgnoreCase("rock")) && !(choice.equalsIgnoreCase("paper")) && !(choice.equalsIgnoreCase("scissors")))
{
System.out.print("Invalid input, enter rock, paper, or scissors: ");
choice = keyboard.nextLine();
}
return true;
}
public static void determineWinner(String computer, String user)
{
if (computer.equalsIgnoreCase("rock") && user.equalsIgnoreCase("paper"))
System.out.println("\n" + "Paper wraps rock.\nThe user wins!");
else if (computer.equalsIgnoreCase("rock") && user.equalsIgnoreCase("scissors"))
System.out.println("\n" + "Rock smashes scissors.\nThe computer wins!");
else if (computer.equalsIgnoreCase("paper") && user.equalsIgnoreCase("rock"))
System.out.println("\n" + "Paper wraps rock.\nThe computer wins!");
else if (computer.equalsIgnoreCase("paper") && user.equalsIgnoreCase("scissors"))
System.out.println("\n" + "Scissors cuts paper.\nThe user wins!");
else if (computer.equalsIgnoreCase("scissors") && user.equalsIgnoreCase("rock"))
System.out.println("\n" + "Rock smashes scissors.\nThe user wins!");
else if (computer.equalsIgnoreCase("scissors") && user.equalsIgnoreCase("paper"))
System.out.println("\n" + "Scissors cuts paper.\nThe computer wins!");
else if (computer.equalsIgnoreCase(user))
System.out.println("\n" + "The game is tied!\nGet ready to play again...");
}
}回答 2
Stack Overflow用户
发布于 2018-10-29 09:46:09
问题源于Java通过值传递，而不是通过引用传递。
换句话说，不是传递给方法的参数的引用，而是传递参数的副本。您的方法更改了副本，但是一旦方法结束，副本就会超出范围并被垃圾回收。
当你通过choice进入isvalidChoice，提及的选择本身没有通过。制作字符串的副本然后传递。更新变量选项时，它不会更改原始字符串，而是更改系统所创建的副本。这个答案解释了它如何运作得很好。
那你该怎么办？
如果它不是有效输入，isValidChoice则isValidChoice返回false 而不是循环。
你isValidChoice应该看起来像这样：
public static boolean isValidChoice(String choice) {
return (choice.equalsIgnoreCase("rock")) || (choice.equalsIgnoreCase("paper")) || (choice.equalsIgnoreCase("scissors"));
}
然后做这样的事情 userChoice
Scanner keyboard = new Scanner(System.in);
while(!isValidChoice(choice)) {
System.out.print("Invalid input, enter rock, paper, or scissors: ");
choice = keyboard.nextLine();
}Stack Overflow用户
发布于 2018-10-29 10:07:11
包装实践程序;
import java.util.Random; import java.util.Scanner;
公共类Rock_Paper_Scissors {
@SuppressWarnings({ "resource" })
public static void main(String[] args) {
Random rand = new Random();
Scanner scan = new Scanner (System.in);
int totalscuser = 0;
int compans = 0;
int totalsccpu = 0;
System.out.println("Rock Paper Scissors!"+"\n"+"Rock: '0'"+ "\n" +"Paper: '1'"+"\n"+"Scissors: '2'");
System.out.println("It's best out of 3!");
for(int i = 0; i<3; i++){
compans = rand.nextInt(3);
compans = rand.nextInt(3);
int inp = scan.nextInt();
if(inp == compans){
System.out.println("Tie");
}else if((inp-1) == compans){
if(inp>2){
System.err.println("Enter a valid input."+"\n"+"CPU Wins because user entered an invalid input.");
totalsccpu = totalsccpu + 1;
}else{
System.out.println("User Wins");
totalscuser = totalscuser + 1;
}
}else if((inp) == compans-1){
if(inp>2){
System.err.println("Enter a valid input."+"\n"+"CPU Wins because user entered an invalid input.");
totalsccpu = totalsccpu + 1;
}else{
System.out.println("CPU Wins");
totalsccpu = totalsccpu + 1;
}
}else if((inp-2) == compans){
if(inp>2){
System.err.println("Enter a valid input."+"\n"+"CPU Wins because user entered an invalid input.");
totalsccpu = totalsccpu + 1;
}else{
System.out.println("CPU Wins");
totalsccpu = totalsccpu + 1;
}
}else if((inp) == compans-2){
if(inp>2){
System.err.println("Enter a valid input."+"\n"+"CPU Wins because user entered an invalid input.");
totalsccpu = totalsccpu + 1;
}else{
System.out.println("User Wins");
totalscuser = totalscuser + 1;
}
}else{
System.err.println("Enter a valid input."+"\n"+"CPU Wins because user entered an invalid input.");
totalsccpu = totalsccpu + 1;
}
System.out.println("CPU entered: "+compans);
}
if(totalsccpu>totalscuser){
System.err.println("YOU LOSE! :(");
}else if(totalsccpu<totalscuser){
System.err.println("YOU WIN! :]");
}if(totalsccpu == totalscuser){
System.err.println("YOU TIED! :|");
}
}
}
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/-100008920
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