swing - Beginner Programming in Java - using an integer in a Dialog (JOptionPane) box from another method -

i have started using java , trying write code take inputs using dialogue boxes , transform/manipulate inputs further

i can desired answer if use 1 method trying use multiple methods. believe incorrectly trying retrieve values other methods not sure going wrong. here have written far - objective take input numbers , swap them , add 100 , 50 swapped numbers , display in dialogue boxes.

i believe error fourth method because when try refer number1 or number2 in

my code follows:

import javax.swing.joptionpane;   public class numberswap {     public static void main(string[] args)    {       greeting();       getfirstnumber();       getsecondnumber();       swapnumber();     }      public static void greeting()    {    // display dialog box message , custom title    joptionpane.showmessagedialog(null,"welcome program!", "welcome!", joptionpane.plain_message);    }      public static int getfirstnumber()    {    // obtain user input joptionpane input dialogs    string firstnumber = joptionpane.showinputdialog(null, "please enter number", "first number?", joptionpane.question_message);     // convert string inputs int values    int number1 = integer.parseint(firstnumber);    return number1;    }      public static int getsecondnumber()    {    // obtain user input joptionpane input dialogs    string secondnumber = joptionpane.showinputdialog(null, "please enter number", "second number?", joptionpane.question_message);     // convert string inputs int values    int number2 = integer.parseint(secondnumber);    return number2;    }       public static void swapnumber()    {    // swap number1 , number2 in order , increment  new first number 100 , new second number 50       int swap1 = number2+100;    int swap2 = number1+50;     joptionpane.showmessagedialog(null, "new value of first number " +swap1, "summary", joptionpane.information_message); joptionpane.showmessagedialog(null, "new value of second number " +swap2, "summary", joptionpane.information_message); system.exit(0);    }    }// end class numberswap 

in posted code, call methods, don't use returned values. need "pass" returned values swapnumber.

you should use this:

int num1 = getfirstnumber(); int num2 = getsecondnumber(); swapnumber(num1, num2); 

with

public static void swapnumber(int number1, int number2) {    // swap number1 , number2 in order , increment  new first number 100 , new second number 50       int swap1 = number2+100;    int swap2 = number1+50;    // etc 

some related reading (oracle tutorial):

• returning value method
• defining methods