java 设计作业——简单计算器

设计要求：

设计一个计算器，用GUI画出来一个图形界面，有两个输入框，一个输出框，有4个加减乘除按钮，实现简单的加减乘除功能。

code：

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;

public class cal extends Frame implements ActionListener
{
private Button plus,minus,mul,div;
private TextField Text1,Text2,Text3;
private int a,b;

public cal(){
super("计算器小程序");

plus=new Button("+");
minus=new Button("-");
mul=new Button("*");
div=new Button("/");

Text1=new TextField("输入第一个数",20);
Text2=new TextField("输入第二个数",20);
Text3=new TextField("结果",20);
//Text1.setEditable(false);

this.setSize(300,200);
this.setBackground(Color.blue);
this.setLocation(300,240);
this.setLayout(new FlowLayout(FlowLayout.LEFT));

this.add(Text1);
this.add(Text2);
this.add(Text3);
this.add(plus);
this.add(minus);
this.add(mul);
this.add(div);

plus.addActionListener(this);
minus.addActionListener(this);
mul.addActionListener(this);
div.addActionListener(this);
this.addWindowListener(new Wadapt());

this.setVisible(true);
}

public void actionPerformed(ActionEvent e)
{
a = Integer.parseInt(Text1.getText());
b = Integer.parseInt(Text2.getText());
if(e.getSource()==plus){
String s = String.valueOf(a+b);
Text3.setText(s);}
else if(e.getSource()==minus){
String s = String.valueOf(a-b);
Text3.setText(s);}
else if(e.getSource()==mul){
String s = String.valueOf(a*b);
Text3.setText(s);}
else if(e.getSource()==div){
if (b==0) {Text3.setText("不合法的数据！");}
else {
String s = String.valueOf(a/b);
Text3.setText(s);}
}
}
public static void main(String args[])
{
cal mycal=new cal();
}
}
class Wadapt extends WindowAdapter
{
public void windowClosing(WindowEvent evt)
{
Frame frm=(Frame)evt.getSource();
frm.setVisible(false);
frm.dispose();
System.exit(0);
}
}