利用java做一个简单的计算器:2012年JAVA考试:公共基础-百考试题网

利用java做一个简单的计算器

文章作者 100test 发表时间 2007:03:14 17:35:17
来源 100Test.Com百考试题网

两个类。还只是完成＋、－、×、÷运算而已。GUI只是用了AWT，很简单，相信一看就能懂了。

　　Calculator.java

以下是引用片段：
public class Calculator{
private String result = "0".
private int op = 0,add = 1,sub = 2,mul = 3,div = 4.

private double stringToDouble(String x){
double y = Double.parseDouble(x).
return y.
}
private void operate(String x){
double x1 = stringToDouble(x).
double y = stringToDouble(result).
switch (op){
case 0:
result = x.
break.
case 1:
result = String.valueOf(y x1).
break.
case 2:
result = String.valueOf(y-x1).
break.
case 3:
result = String.valueOf(yx1).
break.
case 4:
if(x1!=0){
result = String.valueOf(y/x1).
}else{
result = "The divisor cant be zero!".
}
break.
}
}

public String opAdd(String x){
operate(x).
op = add.
return result.
}
public String opSubtract(String x){
operate(x).
op = sub.
return result.
}
public String opMultiply(String x){
operate(x).
op = mul.
return result.
}
public String opDivide(String x){
operate(x).
op = div.
return result.
}
public String opEquals(String x){
operate(x).
op = 0.
return result.
}
public void opClean(){
op = 0.
result = "0".
}
}
　　第二个
　　CalculatorGUI.java

以下是引用片段：
import java.awt..
import java.awt.event..
import java.util.EventObject.

public class CalculatorGUI{
private Frame f.
private Panel p1,p2.
private Button b0,b1,b2,b3,b4,b5,b6,b7,b8,b9.
private Button bPoint,bAdd,bDec,bMul,bDiv,bCal.
private TextField tf.
private String s,op.
private Calculator cal = new Calculator().
private boolean ifOp.

public CalculatorGUI(){
f = new Frame("Calculator").
p1 = new Panel().
p2 = new Panel().

b0 = new Button("0").
b1 = new Button("1").
b2 = new Button("2").
b3 = new Button("3").
b4 = new Button("4").
b5 = new Button("5").
b6 = new Button("6").
b7 = new Button("7").
b8 = new Button("8").
b9 = new Button("9").
bPoint = new Button(".").
bAdd = new Button(" ").
bDec = new Button("-").
bMul = new Button("").
bDiv = new Button("/").
bCal = new Button("=").

tf = new TextField(25).
tf.setEditable(false).

}

public void launchFrame(){
f.setSize(220,160).
f.setResizable(false).
f.addWindowListener(new myWindowListener()).
p1.setLayout(new FlowLayout(FlowLayout.CENTER)).
p1.add(tf).
f.add(p1,BorderLayout.NORTH).
p2.setLayout(new GridLayout(4,4)).

b0.addActionListener(new setLabelText_ActionListener()).
b1.addActionListener(new setLabelText_ActionListener()).
b2.addActionListener(new setLabelText_ActionListener()).
b3.addActionListener(new setLabelText_ActionListener()).
b4.addActionListener(new setLabelText_ActionListener()).
b5.addActionListener(new setLabelText_ActionListener()).
b6.addActionListener(new setLabelText_ActionListener()).
b7.addActionListener(new setLabelText_ActionListener()).
b8.addActionListener(new setLabelText_ActionListener()).
b9.addActionListener(new setLabelText_ActionListener()).
bPoint.addActionListener(new setLabelText_ActionListener()).
bAdd.addActionListener(new setOperator_ActionListener()).
bDec.addActionListener(new setOperator_ActionListener()).
bMul.addActionListener(new setOperator_ActionListener()).
bDiv.addActionListener(new setOperator_ActionListener()).
bCal.addActionListener(new setOperator_ActionListener()).

p2.add(b7).
p2.add(b8).
p2.add(b9).
p2.add(bAdd).
p2.add(b4).
p2.add(b5).
p2.add(b6).
p2.add(bDec).
p2.add(b1).
p2.add(b2).
p2.add(b3).
p2.add(bMul).
p2.add(b0).
p2.add(bPoint).
p2.add(bCal).
p2.add(bDiv).
f.add(p2,BorderLayout.SOUTH).
f.setVisible(true).
}

public void setTextFieldText_Temp(){
if (tf.getText().length()<15 &.&. (tf.getText().indexOf(".")==-1 || !s.equals("."))){
tf.setText(tf.getText() s).
}else{
tf.setText((tf.getText() s).substring(0,15)).
}
}
public void setTextFieldText(){
if(ifOp){
ifOp = false.
tf.setText("").
setTextFieldText_Temp().
}else{
setTextFieldText_Temp().
}
}

public static void main(String[] args){
CalculatorGUI calculator = new CalculatorGUI().
calculator.launchFrame().
}

class myWindowListener extends WindowAdapter{
public void windowClosing(WindowEvent e){
System.exit(0).
}
}

class setLabelText_ActionListener implements ActionListener{
public void actionPerformed(ActionEvent e){
Button tempB = (Button)e.getSource().
s = tempB.getLabel().
setTextFieldText().
}
}

class setOperator_ActionListener implements ActionListener{
public void actionPerformed(ActionEvent e){
Button tempB = (Button)e.getSource().
op = tempB.getLabel().
if(op.equals(" ")){
tf.setText(cal.opAdd(tf.getText())).
ifOp = true.
}else if(op.equals("-")){
tf.setText(cal.opSubtract(tf.getText())).
ifOp = true.
}else if(op.equals("*")){
tf.setText(cal.opMultiply(tf.getText())).
ifOp = true.
}else if(op.equals("/")){
tf.setText(cal.opDivide(tf.getText())).
ifOp = true.
}else if(op.equals("=")){
tf.setText(cal.opEquals(tf.getText())).
ifOp = true.
}
}
}
}

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