作业要求
本次作业需要大家制作可编程计算器。
（1）其界面可参考下图，再加上‘（‘ 和 ’）’
（2）点击 25.6 * 14.5 + 2 这11个符号，按‘=’，可输出结果373.2
（3）点击2 / (5.2 + 78) – 6这12个符号, 按‘=’，可输出结果 -5.97596
（4）若输入语法错误的串，如2 / 5.2 + 78 –， 则需报错。
（5）考虑整型和浮点型问题。对于浮点型，还需考虑精度问题。
（6）考虑除0问题。
（7）考虑键盘操作问题。
注意： 要想计算出值来，必须使用翻译模式。再考虑要计算整个算术表达式的值，则使用综合属性 val。本题翻译模式的提示如下：
E TE’{E.val = T.val + E’.val}
E’ +TE’ {E’.val = T.val + E’.val}
E’ -TE’ {_________}
E’ ε {E’.val = 0}
T FT’{T.val = F.val * T’.val}
T’ FT’ {T’.val = F.val T’.val}
T’ /FT’ {_________}
T’ ε {_______}
F (E) {F.val = E.val}
F i {F.val = i.lexval}
对于 E TE’{E.val = T.val + E’.val}， 其代码经过更改如下：
代码实现
package smartcalculator;
import java.awt.*;
import java.awt.event.*;
public class calculator {
public static void main(String[] args) {
// TODO 自动生成的方法存根
CalFrame f= new CalFrame();
}
}
class CalFrame extends Frame{
double d1,d2;
int op=-1;
TextField tf;
CalPanelL p1;
CalPanelR p2;
CalFrame(){
super("Smart Calculator");
setLayout(new FlowLayout(FlowLayout.CENTER,8,10));
setBackground(new Color(100,150,150));
setForeground(Color.white);
setResizable(false);
setSize(300,200);
tf = new TextField(22);
tf.setEditable(false);
tf.setBackground(new Color(108,118,103));
tf.setForeground(Color.white);
tf.setFont(new Font("Arial",Font.BOLD,16));
add(tf);
p1=new CalPanelL();
p2=new CalPanelR();
add(p1);
add(p2);
setVisible(true);
addWindowListener(new Wclose());
}
class CalButton extends Button{
CalButton(String s){
super(s);
setBackground(Color.gray);
}
}
class CalPanelL extends Panel{
CalButton b0,b1,b2,b3,
b4,b5,b6,b7,
b8,b9,bPN,bPoint;
CalPanelL(){
setLayout(new GridLayout(4,3));
setFont(new Font("TimesRoman",Font.BOLD,16));
b0=new CalButton("0");
b1=new CalButton("1");
b2=new CalButton("2");
b3=new CalButton("3");
b4=new CalButton("4");
b5=new CalButton("5");
b6=new CalButton("6");
b7=new CalButton("7");
b8=new CalButton("8");
b9=new CalButton("9");
bPN=new CalButton("+/-");
bPoint=new CalButton(".");
add(b7); b7.addActionListener(new PressB7());
add(b8); b8.addActionListener(new PressB8());
add(b9); b9.addActionListener(new PressB9());
add(b4); b4.addActionListener(new PressB4());
add(b5); b5.addActionListener(new PressB5());
add(b6); b6.addActionListener(new PressB6());
add(b1); b1.addActionListener(new PressB1());
add(b2); b2.addActionListener(new PressB2());
add(b3); b3.addActionListener(new PressB3());
add(b0); b0.addActionListener(new PressB0());
add(bPN); bPN.addActionListener(new PressBPN());
add(bPoint); bPoint.addActionListener(new PressBPoint());
}
}
class CalPanelR extends Panel{
CalButton bAdd,bSub,bMul,bDiv,
bSqrt,bSin,bCos,bYx,
bLn,bEqual,bCE,bBack;
CalPanelR(){
setLayout(new GridLayout(4,3));
setFont(new Font("TimesRoman",Font.BOLD,16));
bAdd=new CalButton("+");
bSub=new CalButton("-");
bMul=new CalButton("*");
bDiv=new CalButton("/");
bSqrt=new CalButton("sqrt");
bSin=new CalButton("sin");
bCos=new CalButton("cos");
bYx=new CalButton("y^x");
bLn=new CalButton("ln");
bEqual=new CalButton("=");
bCE=new CalButton("CE");
bBack=new CalButton("<-");
add(bDiv);bDiv.addActionListener(new PressBDiv());
add(bSqrt);bSqrt.addActionListener(new PressBSqrt());
add(bLn);bLn.addActionListener(new PressBLn());
add(bMul);bMul.addActionListener(new PressBMul());
add(bSin);bSin.addActionListener(new PressBSin());
add(bBack);bBack.addActionListener(new PressBBack());
add(bSub);bSub.addActionListener(new PressBSub());
add(bCos);bCos.addActionListener(new PressBCos());
add(bCE);bCE.addActionListener(new PressBCE());
add(bAdd);bAdd.addActionListener(new PressBAdd());
add(bYx);bYx.addActionListener(new PressBYx());
add(bEqual);bEqual.addActionListener(new PressBEqual());
}
}
class PressBAdd implements ActionListener{
public void actionPerformed(ActionEvent e){
try{
d1= Double.parseDouble(tf.getText());
op=0;
tf.setText("");
}catch(Exception ee){}
}
}
class PressBSub implements ActionListener{
public void actionPerformed(ActionEvent e){
try{
d1= Double.parseDouble(tf.getText());
op=1;
tf.setText("");
}catch(Exception ee){}
}
}
class PressBMul implements ActionListener{
public void actionPerformed(ActionEvent e){
try{
d1= Double.parseDouble(tf.getText());
op=2;
tf.setText("");
}catch(Exception ee){}
}
}
class PressBDiv implements ActionListener{
public void actionPerformed(ActionEvent e){
try{
d1= Double.parseDouble(tf.getText());
op=3;
tf.setText("");
}catch(Exception ee){}
}
}
class PressBYx implements ActionListener{
public void actionPerformed(ActionEvent e){
try{
d1= Double.parseDouble(tf.getText());
op=4;
tf.setText("");
}catch(Exception ee){}
}
}
class PressBEqual implements ActionListener{
public void actionPerformed(ActionEvent e){
try{
double result=0;
d2=Double.parseDouble(tf.getText());
switch(op){
case 0:
result=d1+d2;
break;
case 1:
result=d1-d2;
break;
case 2:
result=d1*d2;
break;
case 3:
result=d1/d2;
break;
case 4:
result=Math.pow(d1,d2);
break;
default:
}
tf.setText(String.valueOf(result));
}catch(Exception ee){}
}
}
class PressBSqrt implements ActionListener{
public void actionPerformed(ActionEvent e){
try{
double x= Double.parseDouble(tf.getText());
double y;
y=Math.sqrt(x);
tf.setText(y+"");
}catch(Exception ee){}
}
}
class PressBLn implements ActionListener{
public void actionPerformed(ActionEvent e){
try{
double x= Double.parseDouble(tf.getText());
double y;
y=Math.log(x);
tf.setText(y+"");
}catch(Exception ee){}
}
}
class PressBSin implements ActionListener{
public void actionPerformed(ActionEvent e){
try{
double x= Double.parseDouble(tf.getText());
double y;
y=Math.sin(x);
tf.setText(y+"");
}catch(Exception ee){}
}
}
class PressBCos implements ActionListener{
public void actionPerformed(ActionEvent e){
try{
double x= Double.parseDouble(tf.getText());
double y;
y=Math.cos(x);
tf.setText(y+"");
}catch(Exception ee){}
}
}
class PressBBack implements ActionListener{
public void actionPerformed(ActionEvent e){
try{
String text=tf.getText();
text= text.substring(0, text.length()-1);
tf.setText(text);
}catch(Exception ee){}
}
}
class PressBCE implements ActionListener{
public void actionPerformed(ActionEvent e){
tf.setText("");
}
}
class PressBPN implements ActionListener{
public void actionPerformed(ActionEvent e){
try{
String text=tf.getText();
if(text != ""){
if(text.charAt(0)=='-')
tf.setText(text.substring(1));
else if (text.charAt(0)>='0'&&text.charAt(0)<='9')
tf.setText('-'+text.substring(0));
else if(text.charAt(0)=='.')
tf.setText("-0"+text.substring(0));
}
}catch(Exception ee){}
}
}
class PressBPoint implements ActionListener{
public void actionPerformed(ActionEvent e){
String text=tf.getText();
if(text.lastIndexOf(".")==-1)
tf.setText(text+".");
}
}
class PressB0 implements ActionListener{
public void actionPerformed(ActionEvent e){
String text=tf.getText();
tf.setText(text+"0");
}
}
class PressB1 implements ActionListener{
public void actionPerformed(ActionEvent e){
String text=tf.getText();
tf.setText(text+"1");
}
}
class PressB2 implements ActionListener{
public void actionPerformed(ActionEvent e){
String text=tf.getText();
tf.setText(text+"2");
}
}
class PressB3 implements ActionListener{
public void actionPerformed(ActionEvent e){
String text=tf.getText();
tf.setText(text+"3");
}
}
class PressB4 implements ActionListener{
public void actionPerformed(ActionEvent e){
String text=tf.getText();
tf.setText(text+"4");
}
}
class PressB5 implements ActionListener{
public void actionPerformed(ActionEvent e){
String text=tf.getText();
tf.setText(text+"5");
}
}
class PressB6 implements ActionListener{
public void actionPerformed(ActionEvent e){
String text=tf.getText();
tf.setText(text+"6");
}
}
class PressB7 implements ActionListener{
public void actionPerformed(ActionEvent e){
String text=tf.getText();
tf.setText(text+"7");
}
}
class PressB8 implements ActionListener{
public void actionPerformed(ActionEvent e){
String text=tf.getText();
tf.setText(text+"8");
}
}
class PressB9 implements ActionListener{
public void actionPerformed(ActionEvent e){
String text=tf.getText();
tf.setText(text+"9");
}
}
class Wclose extends WindowAdapter{
public void windowClosing(WindowEvent e){
System.exit(0);;
}
}
}
