JAVA课程设计--简易计算器. 求源代码.

import javax.swing.*;//新的窗口组件包
import java.awt.*;
import java.awt.event.*;
public class Jisuanqi implements ActionListener
{ JFrame jf=new JFrame();
boolean dotExist, operated, equaled; // 帮助运算的布尔变量
double result; // 目前的结果
char lastOperator; // 表示上一运算符
JTextField jtf; // 显示栏
JButton dot, plus, minus, multi, div, sqrt, equal, change, clear,quyu; // 运算符
JButton[] numbers;
Panel p=new Panel();
// 构造者
public Jisuanqi()
{
jf.setTitle("陈巳伟牌计算器");
// 初始化变量
dotExist = false; // 表示当前的数是否有小数点
operated = false; // 表示任意运算符是否被按下
equaled = false; // 表示等号是否被按下
result = 0;
lastOperator = '?';
// 初始化窗口变量
jtf = new JTextField("0");
jtf.setEditable(false); //设置文本框的可编辑性
jf.setSize(250,200);
jf.setVisible(true);
numbers = new JButton[10];
for (int i = 0; i < 10; i++)
numbers[i] = new JButton("" + i);
dot = new JButton(".");
plus = new JButton("+");
minus = new JButton("-");

multi = new JButton("*");
div = new JButton("/");
sqrt = new JButton("√");
equal = new JButton("=");
change= new JButton("±");
clear = new JButton("NC");
quyu=new JButton("%");

p.setLayout(new GridLayout(5,4));
p.add(numbers[1]);
p.add(numbers[2]);
p.add(numbers[3]);
p.add(plus);
p.add(numbers[4]);
p.add(numbers[5]);
p.add(numbers[6]);
p.add(minus);
p.add(numbers[7]);
p.add(numbers[8]);
p.add(numbers[9]);
p.add(multi);
p.add(dot);
p.add(numbers[0]);
p.add(sqrt);
p.add(div);
p.add(equal);
p.add(change);
p.add(clear);
p.add(quyu);
jf.add(jtf,BorderLayout.NORTH);
jf.add(p,BorderLayout.CENTER);
numbers[0].addActionListener(this);
numbers[1].addActionListener(this);
numbers[2].addActionListener(this);
numbers[3].addActionListener(this);
plus.addActionListener(this);
numbers[4].addActionListener(this);
numbers[5].addActionListener(this);
numbers[6].addActionListener(this);
minus.addActionListener(this);
numbers[7].addActionListener(this);
numbers[8].addActionListener(this);
numbers[9].addActionListener(this);
multi.addActionListener(this);
dot.addActionListener(this);
sqrt.addActionListener(this);
div.addActionListener(this);
equal.addActionListener(this);
change.addActionListener(this);
clear.addActionListener(this);
quyu.addActionListener(this);

}
// 对按钮进行反应的方法
public void actionPerformed(ActionEvent e)
{
JButton btn = (JButton)e.getSource();
if (btn == clear)
{
jtf.setText("0");
dotExist = false;
operated = false;
equaled = false;
result = 0;
lastOperator = '?';
}
else if (btn == equal)
{
operate('=');
equaled = true;
}
else if (btn == plus)
{
operate('+');
equaled = false;
}
else if (btn == minus)
{
operate('-');
equaled = false;
}
else if (btn == multi)
{
operate('*');
equaled = false;
}
else if (btn == div)
{
operate('/');
equaled = false;
}
else if (btn==quyu){
operate('%');
equaled=false;
}
else if (btn == change)
{
operate('p');
operate('=');
equaled = true;
}
else if (btn == sqrt)
{
operate('s');
operate('=');
equaled = true;
}
else
{
if (equaled)
result = 0;
for (int i = 0; i < 10; i++)
if (btn == numbers[i])
{
if (jtf.getText().equals("0"))
jtf.setText("" + i);
else if(! operated)
jtf.setText(jtf.getText() + i);
else
{
jtf.setText("" + i);
operated = false;
}
}
if (btn == dot && ! dotExist)
{
jtf.setText(jtf.getText() + ".");

}
}
}
// 进行运算的方法
private void operate(char operator)
{
double currentNumber = Double.valueOf(jtf.getText()).doubleValue();
if (lastOperator == '?')
result = currentNumber;
else if (lastOperator == '+')
result += currentNumber;
else if (lastOperator == '-')
result -= currentNumber;
else if (lastOperator == '*')
result *= currentNumber;
else if (lastOperator == '/')
result /= currentNumber;
else if(lastOperator=='%')
result %=currentNumber;
else if (lastOperator == 'p')
result *= -1;
else if (lastOperator == 's')
result = Math.sqrt(currentNumber);
else if (lastOperator == '=' && equaled)
result = currentNumber;
jtf.setText("" + result);
operated = true;
lastOperator = operator;
}

public static void main(String[] args)
{new Jisuanqi();

}
}