Question

This Java program is giving me a good amount of trouble. Can someone solve this for me and provide explanations? I use BlueJ.

Create a class named DLD_JFrame_Arithmetic with a JFrame that accepts two numbers. It is the first time we will use numbers with a JFrame. JTextFields take all inputs as Strings. They must be converted.  int num = Integer.parseInt(number.getText()); We will create Three JLabels, two which prompt user to enter numbers in the JTextFields. The third will be for output. We will need two JTextFields, one for each number entered. We will need four JButtons. A button for each Add, Subtract, Multiply, and Divide. Each button will perform what its text says. Remember also, dividing by zero is an error, so you must account for it with an if statement.

Answer 1

Dear Student,

Thanks for posting an interesting question of Java Programming language where you want to create a simple calculator application using Java Swing.

1. For the given question I have created a complete class named as DLD_JFrame_Arithmetic with proper comments to each of the line of the code and saved the file named as DLD_JFrame_Arithmetic.java at D:/.

2. Please find below screenshot of DLD_JFrame_Arithmetic.java file contents with proper comments to each of the line of the code:-

DaWN import java.awt.event. ActionEvent; import java.awt.event. ActionListener; import javax.swing. JButton; import javax.swing.JFrame; import javax.swing. JLabel; import javax.swing.JTextField; //Creating class DLD_JFrame_Arithmetic which is extending JFrame public class DLD_JFrame_Arithmetic extends JFrame { //Constructor to initialize various control elements of frame public DLD_JFrame_Arithmetic() { HHHHHHHHHH 00 OYO //Creating lbli with message Enter first no and setting its position x,y,width and height JLabel lbll=new JLabel("Enter first no: "); lbli.setBounds (50, 50, 100, 25); // Creating txt1 where user will enter first no as input and setting its position x,y,width and height JTextField txt1=new JTextField(); txt1.setBounds (200, 50, 100, 25); //Creating lbl2 with message Enter second no and setting its position x,y,width and height JLabel lbl2=new JLabel("Enter second no: "); lbl2.setBounds (50, 100, 100, 25); // Creating txt2 where user will enter second no as input and setting its position x,y,width and height JTextField txt2=new JTextField(); txt2.setBounds (200, 100, 100, 25); CO OY O //Creating lbl3 where we will get our final result and setting its position x,y,width and height

JLabel lbl3=new JLabel(); lbl3.setBounds (50, 400, 200, 25); //Creating btn for addition and setting its position x,y,width and height JButton btnAdd=new JButton ("Add"); btnAdd.setBounds (50, 150, 100, 25); //In below statement we are binding the function call on click of button btnAdd. addActionListener(new ActionListener() { @Override public void actionPerformed (ActionEvent e) { try { // Getting number1 from the JTextField and parsing it into int type int num1=Integer.parseInt(txt1.getText()); око о о л ь о оноо оо л о оноо юмом кон 1/Getting number2 from the JTextField and parsing it into int type int num2=Integer.parseInt(txt2.getText()); //Performing addition of num1 and num2 and storing it into result of int type int result=numi+num2; // Setting the result into the lbl3 lbl3.setText ("Addition of "+num1+" and "+num2+" is "+result); } catch (Exception e) { //If any exception will occur then we will set the text Error inside lbl3 lbl3.setText ("Error");

//Creating btn for subtraction and setting its position x,y,width and height JButton btnSub=new JButton("Subtract"); btnSub.setBounds (160, 150, 100, 25); 66 //In below statement we are binding the function call on click of button btnSub.addActionListener(new ActionListener() { @Override public void actionPerformed (ActionEvent e) { try { // Getting number1 from the JTextField and parsing it into int type int numl=Integer.parseInt(txt1.getText()); //Getting number2 from the JTextField and parsing it into int type int num2=Integer.parseInt(txt2.getText()); OOOOOOOOO 0 00 00 00 00 00 00 00 00 00 01 //Performing subtraction of num1 and num2 and storing it into result of int type int result=numl-num2; // Setting the result into the lbl3 lbl3.setText ("Subtraction of "+num1+" and "+num2+" is "+result); } catch (Exception e) { //If any exception will occur then we will set the text Error inside lbl3 lbl3.setText ("Error"); }); //Creating btn for multiplication and setting its position x,y,width and height JButton btnMul=new JButton ("Multiply");

btnMul.setBounds (270, 150, 100, 25); //In below statement we are binding the function call on click of button btnMul.addActionListener(new ActionListener() { co 0 0 0 0 0 0 0 0 0 OOOOOOOOOO m 0 0 @Override public void actionPerformed (ActionEvent e) { try { //Getting number1 from the JTextField and parsing it into int type int num1=Integer.parseInt(txt1.getText()); // Getting number2 from the JTextField and parsing it into int type int num2=Integer.parseInt(txt2.getText()); //Performing multiplication of num1 and num2 and storing it into result of int type int result=num1*num2; 0 // Setting the result into the lbl3 lbl3.setText ("Multiplication of "+num1+" and "+num2+" is "+result); } catch (Exception el) { //If any exception will occur then we will set the text Error inside lbl3 lbl3.setText ("Error"); ! ! ! 0 //Creating btn for division and setting its position x, y,width and height JButton btnDiv=new JButton ("Divide"); btnDiv.setBounds (380, 150, 100, 25); 0 120

121 //In below statement we are binding the function call on click of button btnDiv.addActionListener(new ActionListener() { @Override public void actionPerformed (ActionEvent e) { try { // Getting number1 from the JTextField and parsing it into int type int num1=Integer.parseInt(txt1.getText()); //Getting number2 from the JTextField and parsing it into int type int num2=Integer.parseInt(txt2.getText()); o N 0 N 9 N 0 ( ( ( ( ( ( HHHHHHHHHHHHHHHHHHHHHHHHHHHHHH OOOW NOW HOW NH ( ( ( ( Р В Р В Р Р Р Р Р Р С //If second number is 0 then the lbl3 text will be set as Error if (num2==0) lbl3.setText ("Error"); else{ //Performing division of num1 and num2 and storing it into result of int type int result=numl/num2; // Setting the result into the lbl3 lbl3.setText ("Division of "+num1+" and "+num2+" is "+result); } catch (Exception e) { //If any exception will occur then we will set the text Error inside lbl3 lbl3.setText ("Error");

Сл NH л Сл л л // Adding all the control elements created above are adding into the JFrame add (lbl1); add (lbl2); add(txt1); add(txt2); add (btnAdd); add (btnSub); add (btnMul); add (btnDiv); add(lb13); л л л л W NOCO OY U 0 0 0 0 160 162 // Setting the size of JFrame setSize(600, 600); 0 164 0 //Exit the application on closing the window setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE) ; //Displaying the JFrame setVisible(true); 0 0 0 0 4 4 4 00 O UW NOCO OY 4 4 4 4 4 4 F public static void main(String[] args) { //Creating the object of DLD_JFrame_Arithmetic class DLD_JFrame_Arithmetic frame=new DLD JFrame Arithmetic();

3. Please find below DLD_JFrame_Arithmetic.java file contents in text format for ready copying with proper comments to each of the line of the code:-

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;

//Creating class DLD_JFrame_Arithmetic which is extending JFrame
public class DLD_JFrame_Arithmetic extends JFrame{

   //Constructor to initialize various control elements of frame
   public DLD_JFrame_Arithmetic() {

       //Creating lbl1 with message Enter first no and setting its position x,y,width and height
       JLabel lbl1=new JLabel("Enter first no:");
       lbl1.setBounds(50, 50, 100, 25);
      
       //Creating txt1 where user will enter first no as input and setting its position x,y,width and height
       JTextField txt1=new JTextField();
       txt1.setBounds(200, 50, 100, 25);

       //Creating lbl2 with message Enter second no and setting its position x,y,width and height
       JLabel lbl2=new JLabel("Enter second no:");
       lbl2.setBounds(50, 100, 100, 25);

       //Creating txt2 where user will enter second no as input and setting its position x,y,width and height
       JTextField txt2=new JTextField();
       txt2.setBounds(200, 100, 100, 25);

       //Creating lbl3 where we will get our final result and setting its position x,y,width and height
       JLabel lbl3=new JLabel();
       lbl3.setBounds(50, 400, 200, 25);

       //Creating btn for addition and setting its position x,y,width and height
       JButton btnAdd=new JButton("Add");
       btnAdd.setBounds(50, 150, 100, 25);
       //In below statement we are binding the function call on click of button
       btnAdd.addActionListener(new ActionListener() {

           @Override
           public void actionPerformed(ActionEvent e) {
               try {
                   //Getting number1 from the JTextField and parsing it into int type
                   int num1=Integer.parseInt(txt1.getText());
                  
                   //Getting number2 from the JTextField and parsing it into int type
                   int num2=Integer.parseInt(txt2.getText());
                  
                   //Performing addition of num1 and num2 and storing it into result of int type
                   int result=num1+num2;
                  
                   //Setting the result into the lbl3
                   lbl3.setText("Addition of "+num1+" and "+num2+" is "+result);
               } catch (Exception e1) {
                   //If any exception will occur then we will set the text Error inside lbl3
                   lbl3.setText("Error");
               }
           }
       });

       //Creating btn for subtraction and setting its position x,y,width and height
       JButton btnSub=new JButton("Subtract");
       btnSub.setBounds(160, 150, 100, 25);

       //In below statement we are binding the function call on click of button
       btnSub.addActionListener(new ActionListener() {

           @Override
           public void actionPerformed(ActionEvent e) {
               try {
                   //Getting number1 from the JTextField and parsing it into int type
                   int num1=Integer.parseInt(txt1.getText());
                  
                   //Getting number2 from the JTextField and parsing it into int type
                   int num2=Integer.parseInt(txt2.getText());
                  
                   //Performing subtraction of num1 and num2 and storing it into result of int type
                   int result=num1-num2;
                  
                   //Setting the result into the lbl3
                   lbl3.setText("Subtraction of "+num1+" and "+num2+" is "+result);
               } catch (Exception e1) {
                   //If any exception will occur then we will set the text Error inside lbl3
                   lbl3.setText("Error");
               }
           }
       });

       //Creating btn for multiplication and setting its position x,y,width and height
       JButton btnMul=new JButton("Multiply");
       btnMul.setBounds(270, 150, 100, 25);
      
      //In below statement we are binding the function call on click of button
       btnMul.addActionListener(new ActionListener() {

           @Override
           public void actionPerformed(ActionEvent e) {
               try {
                   //Getting number1 from the JTextField and parsing it into int type
                   int num1=Integer.parseInt(txt1.getText());
                  
                   //Getting number2 from the JTextField and parsing it into int type
                   int num2=Integer.parseInt(txt2.getText());
                  
                   //Performing multiplication of num1 and num2 and storing it into result of int type
                   int result=num1*num2;
                  
                   //Setting the result into the lbl3
                   lbl3.setText("Multiplication of "+num1+" and "+num2+" is "+result);
               } catch (Exception e1) {
                   //If any exception will occur then we will set the text Error inside lbl3
                   lbl3.setText("Error");
               }
           }
       });

       //Creating btn for division and setting its position x,y,width and height
       JButton btnDiv=new JButton("Divide");
       btnDiv.setBounds(380, 150, 100, 25);
      
      //In below statement we are binding the function call on click of button
       btnDiv.addActionListener(new ActionListener() {

           @Override
           public void actionPerformed(ActionEvent e) {
               try {
                   //Getting number1 from the JTextField and parsing it into int type
                   int num1=Integer.parseInt(txt1.getText());
                  
                   //Getting number2 from the JTextField and parsing it into int type
                   int num2=Integer.parseInt(txt2.getText());
                  
                   //If second number is 0 then the lbl3 text will be set as Error
                   if(num2==0)
                       lbl3.setText("Error");
                   else{
                   //Performing division of num1 and num2 and storing it into result of int type
                   int result=num1/num2;
                  
                   //Setting the result into the lbl3
                   lbl3.setText("Division of "+num1+" and "+num2+" is "+result);
                   }
               } catch (Exception e1) {
                  
                   //If any exception will occur then we will set the text Error inside lbl3
                   lbl3.setText("Error");
               }
           }
       });

      
       //Adding all the control elements created above are adding into the JFrame
       add(lbl1);
       add(lbl2);
       add(txt1);
       add(txt2);
       add(btnAdd);
       add(btnSub);
       add(btnMul);
       add(btnDiv);
       add(lbl3);

       //Setting the size of JFrame
       setSize(600, 600);

       //Exit the application on closing the window
       setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

       //Displaying the JFrame
       setVisible(true);

   }
   public static void main(String[] args) {
      
       //Creating the object of DLD_JFrame_Arithmetic class
       DLD_JFrame_Arithmetic frame=new DLD_JFrame_Arithmetic();
   }
}

4. Please find below compilation screenshot of the above program as the above file is stored at D:/.

C. C:\Windows\system32\cmd.exe -java DLD_JFrame_Arithmetic D:\>javac DLD_JFrame_Arithmetic.java D:\>java DLD_JFrame_Arithmetic

5. Please find below various GUI output screenshots shown in JFrame of the above program for the inputs given:-

Enter first no: Enter second no: Add Subtract Multiply Divide Addition of 25 and 5 is 30

Enter first no: Enter second no: 5 Add Subtract Multiply Divide Subtraction of 25 and 5 is 20

Enter first no: Enter second no: Enter second no: Add 5 Subtract Multiply Divide Multiplication of 25 and 5 is 125

Enter first no: Enter second no: Enter second no: 5 Add S ubtract Multiply Divide Division of 25 and 5 is 5

TO DI Enter first no: Enter second no: Enter second no: Add 0 Subtract Multiply Divide ΕΓΓΟΣ

6. Note:-

i) If you perform divide by 0 then an if statement is added to check the same and Error message will be printed inside the third label.

ii) If you keep blank any of the text field and will press any of the button then you will get the message Error.

iii) If you will enter any double value then also you will get the Error message. Since you have asked to take only integer and our code will fail while parsing double value.

iv) Important part of the code is marked in bold.

7. Though I put comments to each of the line of the code. Still if you have any query please feel free to reach me through comments section. I will be more than happy to help you further.

8. Please upvote if you like my answer.

Thanks!!

Happy Learning!!