Question

2.编写Applet程序实现一个计算器，包括十个数字(0～9)按钮和四个运算符(加、减、乘、除)按钮，以及等号和

编写Applet程序实现一个计算器，包括十个数字(0～9)按钮和四个运算符(加、减、乘、除)按钮，以及等号和清空两个辅助按钮，还有一个显示输入输出的文本框。

Answer 1

import java.awt.*;
import java.awt.event.*;
public class num implements ActionListener
{
Frame win=new Frame("CalcV1_0");
Panel num=new Panel();
Panel meth=new Panel();
TextArea display=new TextArea();
Button add1,sub,mul,div;
int no1,no2;
float no3;
String ch,ch3;
Button res=new Button("=");
Button canc=new Button("CE");
Button but7=new Button("7");
Button but8=new Button("8");
Button but9=new Button("9");
Button but4=new Button("4");
Button but5=new Button("5");
Button but6=new Button("6");
Button but1=new Button("1");
Button but2=new Button("2");
Button but3=new Button("3");
Button but0=new Button("0");
public void test()
{
add1=new Button("+");
sub=new Button("-");
mul=new Button("*");
div=new Button("/");
win.setLayout(new GridLayout(4,0));
num.setLayout(new GridLayout(4,3));
meth.setLayout(new GridLayout(0,4));
num.add(but7);
num.add(but8);
num.add(but9);
num.add(but4);
num.add(but5);
num.add(but6);
num.add(but1);
num.add(but2);
num.add(but3);
num.add(but0);
num.add(canc);
num.add(res);
but0.addActionListener(this);
but1.addActionListener(this);
but2.addActionListener(this);
but3.addActionListener(this);
but4.addActionListener(this);
but5.addActionListener(this);
but6.addActionListener(this);
but7.addActionListener(this);
but8.addActionListener(this);
but9.addActionListener(this);
canc.addActionListener(new CE());
add1.addActionListener(new METH());
sub.addActionListener(new METH());
mul.addActionListener(new METH());
div.addActionListener(new METH());
res.addActionListener(new RES());
add1.setSize(10, 10); meth.add(add1);
meth.add(sub); meth.add(mul);
meth.add(div); win.add(display);
win.add(num); win.add(meth);
win.setSize(400,400);
win.setVisible(true);
win.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
}
);
}
public void actionPerformed(ActionEvent e)
{
display.append(e.getActionCommand());
}
private class CE implements ActionListener
{
public void actionPerformed(ActionEvent ex)
{
display.setText("");
no1=0;
no2=0;
no3=0;
}
}
private class METH implements ActionListener
{
public void actionPerformed(ActionEvent ey)
{
no1=Integer.parseInt(display.getText());
display.setText("");
ch=ey.getActionCommand();
}
}
private class RES implements ActionListener
{
public void actionPerformed(ActionEvent es)
{
no2=Integer.parseInt(display.getText());
if(ch=="+")
{
no3=no1+no2;
ch3=Float.toString(no3);
display.setText(ch3);
}
else if(ch=="-")
{
no3=no1-no2;
ch3=Float.toString(no3);
display.setText(ch3);
}
else if(ch=="*")
{
no3=no1*no2;
ch3=Float.toString(no3);
display.setText(ch3);
}
else if(ch=="/")
{
no3=(float)no1/no2;
ch3=Float.toString(no3);
display.setText(ch3);
}
}
}
public static void main (String[]args)
{
num s=new num();
s.test();
}
}