import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/**
 *
 * @author Ankaj Gupta
 */
class ComboboxAddition {         
  private JFrame frame= new JFrame();
  private JPanel panel = new JPanel();
  
  ComboboxAddition() {
    panel.setLayout (null);
 /* Add A label and combobox */ 
   JLabel al = new JLabel ("A :");
     al.setFont(new Font("Serif", Font.BOLD,30)); 
     al.setBounds(30, 40, 280, 45);
     panel.add (al); 
   JComboBox combo_box1 = new JComboBox ();
     combo_box1.setBounds(200, 50, 80, 30);
     for (int i = 20; i >= 1; i--){
        combo_box1.addItem (i);
     }
     panel.add (combo_box1);   
        
  /* Add B label and combobox */             
   JLabel bl = new JLabel ("B :");
     bl.setFont(new Font("Serif", Font.BOLD,30)); 
     bl.setBounds (30, 90, 280, 45);
     panel.add (bl);                  
   JComboBox combo_box2 = new JComboBox ();
     combo_box2.setBounds (200, 100, 80, 30); 
     for (int i = 1; i <= 31; i++){
        combo_box2.addItem (i);
     }
     panel.add (combo_box2);
                 
 /* Add total label and JTextField */         
   JLabel totalL = new JLabel ("Total :");
     totalL.setFont(new Font("Serif", Font.BOLD,30)); 
     totalL.setBounds (400, 30, 280, 45);
     panel.add (totalL); 
   JTextField sum = new JTextField ();
     sum.setEditable(false);
     sum.setFont(new Font("Serif", Font.BOLD,25));
     sum.setForeground (Color.RED);
     sum.setBounds (405, 80, 200, 35);
     panel.add(sum);           
     
 /* Add button  Add*/
  JButton add = new JButton ("Add");
    add.setBackground(Color.BLUE);
    add.setForeground (Color.WHITE);
    add.setFont(new Font("Serif", Font.BOLD,30));
    add.setBounds (280, 200, 120, 45);
    panel.add (add);
    
    frame.add(panel);    
    frame.setSize(700,350);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);      
    
    add.addActionListener(new ActionListener(){       
      @Override
      public void actionPerformed(ActionEvent e){ 
        try{
          int get_a= (int)combo_box1.getSelectedItem();  
          int get_b= (int)combo_box2.getSelectedItem();   
          int total=get_a+get_b;  
          sum.setText(""+total);
          
          System.out.println(total);            
       }
       catch(Exception error){
          System.out.println(error);             
       }            
     }
   });
  }                
  public static void main(String arg[]){
     ComboboxAddition obj= new ComboboxAddition(); 
  }
}