Java显示不显示整个方法

Question

一整天都在为此烦恼。请帮我。我无法显示问题输出显示

问题 1

答案:0

正确....

问题 2

答案:1

错误....

它必须显示:

问题 1

10 + 11 = ?

答案:21

正确...*/

import java.util.Random;
import java.util.*;
import java.util.Scanner;
import javax.swing.JOptionPane;
import java.lang.Math;


public class MathIsSuperFun1{

Scanner input = new Scanner(System.in);
int correctAnswers;
int randomNum1;
int randomNum2;
int choice;
int corrrectAnswers, wrongAnswers;
String playerName ="";
int operation;
int userAnswer;
int correctAnswer = 0;
int userRemainder, correctRemainder;
int x = 0;
int temporaryNum1, temporaryNum2;
int range;
int randomNumber;


public static void main (String args[]){
MathIsSuperFun1 lab = new MathIsSuperFun1();
        lab.init();
    }

public void init(){ 

getName();
pickDifficulty();
pickOperation();
for(int x = 0; x < 10; x++)
{
System.out.println("\t\t\t~~~~~~~PROBLEM NUMBER" + (x + 1) + "~~~~~~~~");
assignNum();
getProblem();
checkAnswer();

}
}

//GET PLAYER NAME USING PANE
public static String getName(){
String playerName;


playerName = JOptionPane.showInputDialog(null, "Welcome!\nEnter your name and press OK.", "Math Is Super Fun!", JOptionPane.QUESTION_MESSAGE);
System.out.println("Do your best," + playerName + "!");
return playerName;
}

//GET PROBLEM BASED ON OPERATION
    public void getProblem(){
    switch(operation){

        case 1:
            System.out.println(randomNum1 + "+" + randomNum2 + "= ?\n");
            correctAnswer = randomNum1 + randomNum2;
            break;

        case 2:
            System.out.println(randomNum1 + "-" + randomNum2 + "= ?\n");
            correctAnswer = randomNum1-randomNum2;
            break;
        case 3:
            System.out.println(randomNum1 + "*" + randomNum2 + "= ?\n");
            correctAnswer = randomNum1*randomNum2;
            break;
        case 4:
            System.out.println(randomNum1 + "/" + randomNum2 + "= ?\n");
            correctAnswer = randomNum1/randomNum2;
            correctRemainder = randomNum1%randomNum2;
            break;
    }

        System.out.print("Answer: ");
        userAnswer = input.nextInt();
        if(operation == 4){
        System.out.print("Remainder: ");
        userRemainder = input.nextInt();
        }
        return 0;



    }



//PICK DIFFICULTY USING DIALOG
public void pickDifficulty(){
int choice = 0;
System.out.println("1 - Child's Play\n2 - No Sweat\n3 - Bitter\n4 - Cold-blooded\n5 - Brutal\n6 - Genius");
choice = input.nextInt();
}

//PICK OPERATIONS
public void pickOperation(){
int operation = 0;

System.out.println("1 - Addition\n2 - Subtraction\n3 - Multiplication\n4 - Division ");
operation = input.nextInt();

}

//GET NUMBER RANGE BASED ON DIFFICULTY
public int numberRange(){
int range = 0;

switch(choice){

case 1:
range = 100;
break;

case 2:
range = 1000;
break;

case 3:
range = 10000;
break;

case 4:
range = 100000;
break;

case 5:
range = 1000000;
break;

case 6:
range = 10000000;
break;
}
return range;
}

//GET CORRECT RANDOM RESPONSE USING CASE SWITCH BASED ON GETRANDOM METHOD
public void correctResponse(){
String responseCorrect = "";

switch (getRandom(5)){

        case 1:
        responseCorrect = "Correct. Keep up the good work!";
        break;

        case 2:
        responseCorrect = "Correct. Keep aiming higher!";
        break;

        case 3:
        responseCorrect = "Correct. Well done!";
        break;

        case 4:
        responseCorrect = "Correct. Nice work!";
        break;

        case 5:
        responseCorrect = "Correct. We're almost there!";
        break;
        }

        System.out.println(responseCorrect);
        correctAnswers += 1;
}

//GET WRONG RANDOM RESPONSE USING CASE SWITCH BASED ON GETRANDOM METHOD
public String wrongResponse(){
String responseWrong = "";
switch (getRandom(5)){

        case 1:
        responseWrong = "Wrong. Don't give up!";
        break;

        case 2:
        responseWrong = "Wrong. You can do it!";
        break;

        case 3:
        responseWrong = "Wrong. Try again puny human!";
        break;

        case 4:
        responseWrong = "Wrong. You must be really weak at math!";
        break;

        case 5:
        responseWrong = "Wrong. I pity you!";
        break;
        }

        System.out.println(responseWrong);
        System.out.println("The correct answer is:" + correctAnswer);
        if(operation == 4)
        System.out.println("Correct Remainder: " + correctRemainder);
        return responseWrong;
    }




public void checkAnswer(){

        if(operation != 4 && userAnswer == correctAnswer){
            correctResponse();
        }
        else if(operation == 4 && userAnswer == correctAnswer && userRemainder == correctRemainder){
            correctResponse();
        }
        else{
            wrongResponse();
        }
    }

public void assignNum(){

    int temporaryNum1 = getRandom(numberRange());
    int temporaryNum2 = getRandom(numberRange());
    while(operation == 4 && temporaryNum1 == 0){
            temporaryNum1 = getRandom(numberRange());
        }
        while(operation == 4 && temporaryNum2 == 0){
            temporaryNum2 = getRandom(numberRange());
        }
        if(temporaryNum1 > temporaryNum2)
        {
            randomNum1 = temporaryNum1;
            randomNum2 = temporaryNum2;
        }
        else
        {
            randomNum1 = temporaryNum2;
            randomNum2 = temporaryNum1;
        }
    }



    public int getRandom(int range){
    randomNumber = (int)Math.floor((Math.random()*range)+1); 
    return randomNumber;
    }



}

Answer 1

您的问题未输出的原因很简单。

public void pickOperation(){
    int operation = 0;

    System.out.println("1 - Addition\n2 - Subtraction\n3 - Multiplication\n4 - Division ");
    operation = input.nextInt();

 }

您正在创建一个局部变量操作，并向其分配输入值。这意味着 operation 字段永远不会被设置，因此当涉及到 getProblem 方法中的 switch 语句时，它不会被设置。输出任何内容，因为它与 switch 语句不匹配。

要解决此问题，只需删除 int operation = 0; 声明即可。

<小时/>

编辑

刚刚注意到您的 pickDifficulty 方法也存在同样的问题。我强烈建议您看看this tutorial on scope in Java 。

问题说明

好的。那么让我们看看您的代码:

public void pickOperation(){

    int operation = 0;
    // Declare an int, called 'operation'.
    System.out.println("1 - Addition\n2 - Subtraction\n3 - Multiplication\n4 - Division ");
    // Set the newly declared value to an int from the keyboard.
    operation = input.nextInt();
 }

一旦该方法完成，操作内的值就会被销毁。它之所以没有保留在您的字段int operation中，是因为您声明了一个更本地化的operation变量。通过删除此方法开头的 int operation = 0;，您可以强制 JVM 在类中查找下一个名为 operation 的可用变量，该变量位于 field 。这就是为什么当您删除第一个断言语句时，您的 operation 值将保留下来。