How to implement a program to count the number in Java?


The program uses a JLabel to hold a count label, a JTextField component to hold the number count, JButton component to create add, remove and reset buttons. When we click the add button, the count in the JTextField will get incremented by '1' and by clicking the remove button the count will be decremented by '1'. If we click the Reset button, it will reset the count to '0'.

Example

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class CounterTest extends JFrame implements ActionListener {
   private JLabel label;
   private JTextField text;
   private JButton addBtn, removeBtn, resetBtn;
   private int count;
   public CounterTest() {
      setTitle("Counter Test");
      setLayout(new FlowLayout());
      count = 0;
      label = new JLabel("Count:");
      text = new JTextField("0", 4);
      addBtn = new JButton("Add");
      removeBtn = new JButton("Remove");
      resetBtn = new JButton("Reset");
      addBtn.addActionListener(this);
      removeBtn.addActionListener(this);
      resetBtn.addActionListener(this);

      add(label);
      add(text);
      add(addBtn);
      add(removeBtn);
      add(resetBtn);

      setSize(375, 250);
      setLocationRelativeTo(null);
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      setVisible(true);
   }
   public void actionPerformed(ActionEvent ae) {
      if (ae.getSource() == addBtn) {
         count++; // increment the coiunt by 1
         text.setText(String.valueOf(count));
         repaint();
      } else if (ae.getSource() == removeBtn) {
         count--; // decrement the count by 1
         text.setText(String.valueOf(count));
         repaint();
      } else if (ae.getSource() == resetBtn) {
         count = 0; // reset the count to 0
         text.setText(String.valueOf(count));
         repaint();
      }
   }
   public static void main(String[] args) {
      new CounterTest();
   }
}

Output

raja
Published on 15-Jul-2019 18:53:31
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