Java 程序在请求用户输入后停止运行

Question

我的代码可以编译，但一旦运行它，它就会要求用户输入，然后停止。然而，程序说它仍在运行，但它没有继续执行其余的代码，我不明白为什么。

这是我的代码的一部分。当我询问用户他们想回答多少问题后，它就会停止。根据我的调试器，它特别停在“qNum = console.nextInt();”处当我输入有效的输入时。

import java.util.*;
import java.io.*;

public class QuizBowlRedo implements Quiz {  
    private Player player;     // player object
    private String file;       // name of file
    private int qNum;          // number of questions player wants to answer
    private int qNumFile;      // number of questions in file
    private ArrayList<Question> questionsArr; // holds Question objects
    private boolean questionsAsked[];



// Constructor
public QuizBowlRedo(String fName, String lName, String file) throws FileNotFoundException {
    player = new Player(fName, lName);
    Scanner gameFile = new Scanner(new File(file));
    qNum = numOfQuestionsToPlay();
    qNumFile = maxNumQFile(gameFile);
    questionsArr = new ArrayList<Question>();
    readFile();
    questionsAsked = new boolean[qNumFile];    
}

// asks user how many questions to ask
public int numOfQuestionsToPlay() {
    Scanner console = new Scanner(System.in); 

    // CHECKS FOR VALID USER INPUT
    boolean check = false;
    do {
        try {
            System.out.print("How many questions would you like (out of 3)? ");
            if(console.nextInt() > 3) {
                System.out.println("Sorry, that is too many.");
                check = false;
             }               
            else {
                check = true;
                qNum = console.nextInt();           
            }

        }
        catch(InputMismatchException e) {
           System.out.println("Invalid input. Please try again.");
           console.nextLine(); 
           check = false;  
        }
   }
   while(check == false);
   return qNum; 
}

Answer 1

您在程序中的两个不同位置调用 nextInt()，因此如果您的程序进入“else” block ，那么它将再次等待结果。

您应该只调用 nextInt() 一次，并在继续之前将结果分配给局部变量。你可以这样做。

        System.out.print("How many questions would you like (out of 3)? ");
        int answer = console.nextInt();
        if(answer > 3) {
            System.out.println("Sorry, that is too many.");
            check = false;
         }               
        else {
            check = true;
            qNum = answer;           
        }