实验报告 编写一个简易实用的计算器

1、开课实验室：现代信息交流中心40* 开课时间: 2012年*月*日 实验报告: 年 月 日 学院名称 年级、专业、班 学号 姓名 同组姓名无课程名称Java程序设计实验项目名称四、Java图形用户界面开发指导教师尉斌实验类型验证 综合 设计 创新 成绩教师评语 教师签名： 年 月 日一、 实验目的：熟悉Java图形用户界面的开发原理与技术，包括各种组件和容器技术。二、 实验内容：编写一个简易实用的计算器。三、 源代码清单：package exp3;import java.applet.Applet;import java.awt.BorderLayout;import java.awt.But

2、ton;import java.awt.Color;import java.awt.GridLayout;import java.awt.Panel;import java.awt.TextField;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;class Result extends Panel TextField tf;Result() tf = new TextField(0, 25);add(tf);class Key extends Panel Button backSpace, cle

3、arEnter, cancel,lBracket,rBracket;Button one, two, three, four, five, six, seven, eight, nine, zero;Button add, subtract, multiplay, divide;Button sqrt, reciprocal, mod;Button positiveAndNegative, point, equal;Key() setLayout(new GridLayout(5, 5);backSpace = new Button();backSpace.setForeground(new

4、Color(255, 0, 0);add(backSpace);clearEnter = new Button(CE);clearEnter.setForeground(new Color(255, 0, 0);add(clearEnter);cancel = new Button(C);cancel.setForeground(new Color(255, 0, 0);add(cancel); lBracket =new Button();add(lBracket);rBracket =new Button();add(rBracket);seven = new Button(7);add(

5、seven);eight = new Button(8);add(eight);nine = new Button(9);add(nine);divide = new Button(/);add(divide);sqrt = new Button(sqrt);add(sqrt);four = new Button(4);add(four);five = new Button(5);add(five);six = new Button(6);add(six);multiplay = new Button(*);add(multiplay);mod = new Button(%);add(mod)

6、;one = new Button(1);add(one);two = new Button(2);add(two);three = new Button(3);add(three);subtract = new Button(-);add(subtract);reciprocal = new Button(1/x);add(reciprocal);zero = new Button(0);add(zero);positiveAndNegative = new Button(+/-);add(positiveAndNegative);point = new Button(.);add(poin

7、t);add = new Button(+);add(add);equal = new Button(=);add(equal);public class Calculator extends Applet implements ActionListener Result result = new Result();Key key = new Key();boolean isInit = true; String operation = ; float theFirstNum = 0; float theSecondNum = 0; float f = 0;/ 用于括号计算时的使用 Strin

8、g s=;/ 用于括号计算时的使用public void init() setLayout(new BorderLayout();add(North, result); add(Center, key); key.add.addActionListener(this);key.divide.addActionListener(this);key.eight.addActionListener(this);key.equal.addActionListener(this);key.five.addActionListener(this);key.four.addActionListener(th

9、is);key.mod.addActionListener(this);key.multiplay.addActionListener(this);key.nine.addActionListener(this);key.one.addActionListener(this);key.point.addActionListener(this);key.positiveAndNegative.addActionListener(this);key.reciprocal.addActionListener(this);key.seven.addActionListener(this);key.si

10、x.addActionListener(this);key.sqrt.addActionListener(this);key.subtract.addActionListener(this);key.three.addActionListener(this);key.two.addActionListener(this);key.zero.addActionListener(this);key.backSpace.addActionListener(this);key.cancel.addActionListener(this);key.clearEnter.addActionListener

11、(this);key.lBracket.addActionListener(this);key.rBracket.addActionListener(this);public void actionPerformed(ActionEvent e) if (e.getSource() = key.one) if (isInit) result.tf.setText(1); isInit = false; else result.tf.setText(result.tf.getText() + 1);if (e.getSource() = key.two) if (isInit) result.t

12、f.setText(2);isInit = false; else result.tf.setText(result.tf.getText() + 2);if (e.getSource() = key.three) if (isInit) result.tf.setText(3);isInit = false; else result.tf.setText(result.tf.getText() + 3);if (e.getSource() = key.four) if (isInit) result.tf.setText(4);isInit = false; else result.tf.s

13、etText(result.tf.getText() + 4);if (e.getSource() = key.five) if (isInit) result.tf.setText(5);isInit = false; else result.tf.setText(result.tf.getText() + 5);if (e.getSource() = key.six) if (isInit) result.tf.setText(6);isInit = false; else result.tf.setText(result.tf.getText() + 6);if (e.getSource

14、() = key.seven) if (isInit) result.tf.setText(7);isInit = false; else result.tf.setText(result.tf.getText() + 7);if (e.getSource() = key.eight) if (isInit) result.tf.setText(8);isInit = false; else result.tf.setText(result.tf.getText() + 8);if (e.getSource() = key.nine) if (isInit) result.tf.setText

15、(9);isInit = false; else result.tf.setText(result.tf.getText() + 9);if (e.getSource() = key.zero) if(result.tf.getText().equals(0) else result.tf.setText(result.tf.getText() + 0);if (e.getSource() = key.point) if (result.tf.getText().indexOf(.) = -1) result.tf.setText(result.tf.getText() + .);isInit

16、 = false; if (e.getSource() = key.add) theFirstNum = Float.parseFloat(result.tf.getText();operation = add;isInit = true;if (e.getSource() = key.subtract) theFirstNum = Float.parseFloat(result.tf.getText();operation = subtract;isInit = true;if (e.getSource() = key.multiplay) theFirstNum = Float.parse

17、Float(result.tf.getText();operation = multiplay;isInit = true;if (e.getSource() = key.divide) theFirstNum = Float.parseFloat(result.tf.getText();operation = divide;isInit = true;if (e.getSource() = key.mod) theFirstNum = Float.parseFloat(result.tf.getText();operation = mod;isInit = true;if (e.getSou

18、rce() = key.sqrt) theFirstNum = Float.parseFloat(result.tf.getText();result.tf.setText(String.valueOf(Math.sqrt(theFirstNum);isInit = true;if (e.getSource() = key.reciprocal) if (result.tf.getText().equals(0)result.tf.setText(Error);else theFirstNum = Float.parseFloat(result.tf.getText();result.tf.s

19、etText(String.valueOf(1 / theFirstNum);isInit = true; if (e.getSource() = key.positiveAndNegative) if (result.tf.getText().equals(0) else if (result.tf.getText().startsWith(-)result.tf.setText(result.tf.getText().substring(1);elseresult.tf.setText(- + result.tf.getText();if (e.getSource() = key.equa

20、l) theSecondNum = Float.parseFloat(result.tf.getText();if (operation.equals() result.tf.setText(0);if (operation.equals(add)result.tf.setText(String.valueOf(theFirstNum + theSecondNum);if (operation.equals(subtract)result.tf.setText(String.valueOf(theFirstNum - theSecondNum);if (operation.equals(mul

21、tiplay)result.tf.setText(String.valueOf(theFirstNum * theSecondNum);if (operation.equals(divide) if (result.tf.getText().equals(0)result.tf.setText(Error);elseresult.tf.setText(String.valueOf(theFirstNum / theSecondNum);if (operation.equals(mod) if (result.tf.getText().equals(0)result.tf.setText(Err

22、or);elseresult.tf.setText(String.valueOf(theFirstNum % theSecondNum);isInit = true; theFirstNum = 0;theSecondNum = 0;operation = ; if (e.getSource() = key.backSpace) if (result.tf.getText().equals(0)else if (result.tf.getText().length() = 1) result.tf.setText(0);isInit = true; elseresult.tf.setText(

23、result.tf.getText().substring(0,result.tf.getText().length() - 1);if (e.getSource() = key.clearEnter) result.tf.setText(0);isInit = true; if (e.getSource() = key.cancel) result.tf.setText(0);theFirstNum = 0;theSecondNum = 0;operation = ;isInit = true; if (e.getSource() = key.lBracket) f = theFirstNum; / 把第一个数赋给fs = operation; / 把运算符号赋给stheFirstNum = 0;theSecondNum = 0;operation = ;isInit = true; /回到初始化，再次输入的数值为新的开始，但文本域内容不变if (e.getSourc