Thread: Calculator Method issue

Hi, I have a question regarding my code here. It's a simple calculator. It's not necessarily wrong, but I think there is a shorter, better way to do this.

Here is the code:

import javax.swing.*;
public class Java_calculator_3_4 {
 
    static void addition () {
        int a = Integer.parseInt(JOptionPane.showInputDialog("Please enter the first value:"));
        int b = Integer.parseInt(JOptionPane.showInputDialog("Please enter the second value:"));
        int answer = (a+b);
        System.out.println("\nThe answer is " + answer);
        }
 
    static void subtraction () {
        int a = Integer.parseInt(JOptionPane.showInputDialog("Please enter the first value:"));
        int b = Integer.parseInt(JOptionPane.showInputDialog("Please enter the second value:"));
        int answer = (a-b);
        System.out.println("\nThe answer is " + answer);
        }
    static void multiplication () {
        int a = Integer.parseInt(JOptionPane.showInputDialog("Please enter the first value:"));
        int b = Integer.parseInt(JOptionPane.showInputDialog("Please enter the second value:"));
        int answer = (a*b);
        System.out.println("\nThe answer is " + answer);
        }
    static void division () {
        int a = Integer.parseInt(JOptionPane.showInputDialog("Please enter the first value:"));
        int b = Integer.parseInt(JOptionPane.showInputDialog("Please enter the second value:"));
        int answer = (a/b);
        System.out.println("\nThe answer is " + answer);
        }
 
public static void main(String[] args) {
    String arithmeticOperation;
    char selection;
 
    System.out.println("Possible arithmetic operations:\n a\t Addition\n b\t Subtraction\n c\t Multiplication\n d\t Division");
 
    arithmeticOperation = JOptionPane.showInputDialog("Which arithmetic operation would you like to initiate?");
    selection = arithmeticOperation.charAt(0);
 
    switch (selection) {
        case 'a':
            addition();
            break;
        case 'b':
            subtraction();
            break;
        case 'c':
            multiplication();
            break;
        case 'd':
            division();
            break;
            default:
 
        System.out.println("You choice is invalid");
        }
 
        System.exit(0);
    }
}

I'm trying to figure out how I can convert the code so the 'InputDialog' only has to be written once, preferably within the Main Method like the 'arithmeticOperation', and then from there transfer the two entered numbers as arguments back to the methods to be calculated. This means the output also only has to be programmed once. Same issue.

I'm not sure where to begin here, and how to adjust the code accordingly. So any advice and tips would be greatly appreciated.

Thanks

Hi Norm. Thanks for the reply. I don't understand though. Please check this code. It's a simpler version with my idea. I've commented everything so you should be able to see what the issue is. Thanks again.

import javax.swing.JOptionPane;
 
public class Java_methods_p_a {
 
 
    public static void main(String[] args) {
 
 
        //This is where the user chooses the operation. Ill keep it simple and only have 2 options here.
        int operationA =Integer.parseInt( JOptionPane.showInputDialog("Add operation: 1.Addition /t 2.Subtraction"));
 
        //I use a switch case function here as i usually have more than 2 options.
        switch(operationA) {
        case '1':
            System.out.println("+");
            break;
        case '2':
            System.out.println("-");
            break;
 
 
        }
 
            //Here I initialize the variables where the user can enter the 2 numbers.
         int variable1 = Integer.parseInt(JOptionPane.showInputDialog("Add first number:"));
         int variable2 = Integer.parseInt(JOptionPane.showInputDialog("Add second number:"));
 
         System.out.println("The answer is " + ???????  (variable1, variable2));
 
        /*THIS PART IS THE ISSUE!!!!System.out.println("blablabla " + ???????  (variable1, variable2)); What do I add where the ??? are         
       to be able to get the correct output according to the operation the user chooses? So basically if user chooses option 1 which is'+' the 
       output should be from the method 'addition' with 'return(a+b)';.For option 2 the output should be method subtraction 'return(a-b);' Thanks*/
 
 
    }
    //method addition
    static int addition(int a, int b) {
        return(a+b);
 
    }
    //method subtraction
    static int subtraction(int a, int b) {
        return(a-b);
 
    }
 
}