Java display does not show whole method

Question

Having trouble with this the whole day. Please help me. I can't get the problem to display The output shows

PROBLEM NUMBER 1

Answer:0

Correct....

PROBLEM NUMBER 2

Answer:1

Wrong....

It must show:

PROBLEM NUMBER 1

10 + 11 = ?

Answer: 21

Correct...*/

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

The reason your questions are not outputting is simple.

public void pickOperation(){
    int operation = 0;

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

 }

You are creating a local variable, operation, and assigning the input value to it. This means that the field, operation, is never set, so when it comes to the switch statement in your getProblem method, it doesn't output anything because it doesn't match the switch statement.

To fix this, simply remove the int operation = 0; declaration.

---

Edit

Just noticed the same problem with your pickDifficulty method. I would strongly recommend you have a look at this tutorial on scope in Java.

Explanation of your Problem

Okay. So let's look at your code:

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();
 }

As soon as this method is finished, the value inside operation is destroyed. The reason why it isn't staying in your field int operation, is because you declared a more local operation variable. By removing the int operation = 0; at the start of this method, you force the JVM to look for the next available variable named operation in your class, which is in the field. That's why, when you remove the first assertion statement, your value for operation will stick around.

Answer 2

the problem is : int operation = 0; you need to take the value of the operation in operation variable which you create it in Main

Try this :

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

public class Main {

    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[]) {
        Main lab = new Main();
        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();
            getAnswers();
            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() {
        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() {
        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;
    }

    private void getAnswers() {
        ////////////////Not yet implemented";
    }
}