import java.awt.*; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.*; public class Exam01 extends JFrame{ private Label calc_lb= new Label("계산기", Label.CENTER); private TextField tf = new TextField(50); private Button bt0 = new Button("0"); private Button bt1 = new Button("1"); private Button bt2 = new Button("2"); private Button bt3 = new Button("3");..
