Question

我正在创建一个Rock，Paper，Scissors游戏来练习我的Java技能。但是现在，我正面临一个我无法解决的问题。当我要求用户输入某些内容时，他们无法输入内容，而是直接进入后面的if语句。

代码：包rps_game;

// Rock, Paper, Scissors game


import java.util.Scanner;
import java.util.Random;
import java.util.*;

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

        Scanner input = new Scanner(System.in);
        Random rand = new Random();

        String choices[] = {"rock", "paper", "scissors"};

        int winRounds = 0;
        boolean running = true;

        int rounds = 0;
        int wins = 0;
        int loses = 0;

        String yourChoice="";
        String compChoice="";
        while (running = true){ // main loop

            try{
                System.out.println("Enter the amount of rounds you want to play: ");
                rounds = input.nextInt(); // gets input
                winRounds = (rounds/2)+1;
                System.out.println("You are playing best of " + winRounds + " out of " + rounds);

                running = false; // breaks off from loop

            }catch(Exception e){ // if error pops up
                System.out.println("You DID NOT enter a WHOLE NUMBER.");
                // still runs b/c criteria has not been met.
            }

            while (wins < winRounds && loses < winRounds){
                // problem arises here
                System.out.println("Enter either Rock, Paper or Scissors: ");
                yourChoice = input.nextLine();
                input.nextLine();
                yourChoice.toLowerCase();



                if (yourChoice.equals(Arrays.asList(choices).contains(yourChoice))){ // if array contains what use entered
                    break;
                }else{
                    System.out.println("You did not enter either Rock, Paper or Scissors.");
                    running = false; // exit program
                }

                compChoice = choices[rand.nextInt(choices.length)];
                System.out.println(compChoice);

            }

        }

    }
}

我还没有完成它，但是发生了什么？

Answer 1

您必须阅读第String temp = input.nextLine();行，然后在本地创建另一个Scanner以阅读int。因此，用户按下的输入（\ n）将被读取为一行，否则按下的输入将被解释为input.nextLine();

中的另一行

虽然循环是无限循环，但您也可能想要纠正它。

Answer 2

此代码可以纠正您的错误，但您仍需要做很多事情。

问题首先是输入扫描仪。（您需要两个输入扫描仪）

其次，在yourChoice.toLowerCase（）中，它必须是yourChouice = yourChoice.toLowerCase（）; 因为字符串是不可变的。

最后在yourChoice.equals（Arrays.asList（choices）.contains（yourChoice））。这实际上必须是（Arrays.asList（choices）.contains（yourChoice）。

Try Catch位于错误的位置，因此您的整个代码都在运行，请参阅以下代码，没有问题。

import java.util.Scanner;
import java.util.Random;
import java.util.*;

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

        Scanner input = new Scanner(System.in);
        Scanner lineInput = new Scanner(System.in);
        Random rand = new Random();

        String choices[] = { "rock", "paper", "scissors" };

        int winRounds = 0;
        boolean running = true;

        int rounds = 0;
        int wins = 0;
        int loses = 0;

        String yourChoice = "";
        String compChoice = "";
        while (running = true) { // main loop

            try {
                System.out
                        .println("Enter the amount of rounds you want to play: ");
                rounds = input.nextInt(); // gets input
                winRounds = (rounds / 2) + 1;
                System.out.println("You are playing best of " + winRounds
                        + " out of " + rounds);

                running = false; // breaks off from loop

                while (wins < winRounds && loses < winRounds) {
                    System.out
                            .println("Enter either Rock, Paper or Scissors: ");
                    yourChoice = lineInput.nextLine();
                    yourChoice= yourChoice.toLowerCase();
                    if (Arrays.asList(choices).contains(
                            yourChoice)) { // what use entered
                        break;
                    } else {
                        System.out
                                .println("You did not enter either Rock, Paper or Scissors.");
                        running = false; // exit program
                    }

                    compChoice = choices[rand.nextInt(choices.length)];
                    System.out.println(compChoice);

                }
            } catch (Exception e) { // if error pops up
                System.out.println("You DID NOT enter a WHOLE NUMBER.");
                break;
            }

        }

        input.close();
        lineInput.close();
    }
}

Java跳过输入并直接进入if语句，

2 个答案: