import java.awt.*; 
import java.awt.event.*; 
import javax.swing.*; 

public class testZ extends JFrame implements ActionListener{ 
private JPanel jPanel1,jPanel2; 
private JTextField resultField; 
private JButton s1,s2,s3,s4,s5,s6,s7,s8,s9,s0,b1,b2,b3,b4,f1,f2; 
private boolean end,add,sub,mul,div; 
private String str; 
private double num1,num2; 

public testZ(){ 
super("計算器"); 
setSize(300,240); 
Container con=getContentPane(); 
con.setLayout(new BorderLayout()); 
jPanel1=new JPanel(); 
jPanel1.setLayout(new GridLayout(1,1)); 
jPanel2=new JPanel(); 
jPanel2.setLayout(new GridLayout(4,4)); 
resultField=new JTextField("0"); 
jPanel1.add(resultField); 
con.add(jPanel1,BorderLayout.NORTH); 
s1=new JButton(" 1 "); s1.addActionListener(this); 
s2=new JButton(" 2 "); s2.addActionListener(this); 
s3=new JButton(" 3 "); s3.addActionListener(this); 
s4=new JButton(" 4 "); s4.addActionListener(this); 
s5=new JButton(" 5 "); s5.addActionListener(this); 
s6=new JButton(" 6 "); s6.addActionListener(this); 
s7=new JButton(" 7 "); s7.addActionListener(this); 
s8=new JButton(" 8 "); s8.addActionListener(this); 
s9=new JButton(" 9 "); s9.addActionListener(this); 
s0=new JButton(" 0 "); s0.addActionListener(this); 
b1=new JButton(" + "); b1.addActionListener(this); 
b2=new JButton(" - "); b2.addActionListener(this); 
b3=new JButton(" * "); b3.addActionListener(this); 
b4=new JButton(" / "); b4.addActionListener(this); 
f1=new JButton(" . "); f1.addActionListener(this); 
f2=new JButton(" = "); f2.addActionListener(this); 
jPanel2.add(s1); 
jPanel2.add(s2); 
jPanel2.add(s3); 
jPanel2.add(b1); 
jPanel2.add(s4); 
jPanel2.add(s5); 
jPanel2.add(s6); 
jPanel2.add(b2); 
jPanel2.add(s7); 
jPanel2.add(s8); 
jPanel2.add(s9); 
jPanel2.add(b3); 
jPanel2.add(s0); 
jPanel2.add(f1); 
jPanel2.add(f2); 
jPanel2.add(b4); 
con.add(jPanel2,BorderLayout.CENTER); 

} 
public void num(int i){ 
String s = null; 
s=String.valueOf(i); 
if(end){ 
//如果數字輸入結束，則將文本框置零，重新輸入 
resultField.setText("0"); 
end=false; 

} 
if((resultField.getText()).equals("0")){ 
//如果文本框的內容為零，則覆蓋文本框的內容 
resultField.setText(s); 

} 
else{ 
//如果文本框的內容不為零，則在內容后面添加數字 
str = resultField.getText() + s; 
resultField.setText(str); 

} 
} 

public void actionPerformed(ActionEvent e){ //數字事件 
if(e.getSource()==s1) 
num(1); 
else if(e.getSource()==s2) 
num(2); 
else if(e.getSource()==s3) 
num(3); 
else if(e.getSource()==s4) 
num(4); 
else if(e.getSource()==s5) 
num(5); 
else if(e.getSource()==s6) 
num(6); 
else if(e.getSource()==s7) 
num(7); 
else if(e.getSource()==s8) 
num(8); 
else if(e.getSource()==s9) 
num(9); 
else if(e.getSource()==s0) 
num(0); 

//符號事件 
else if(e.getSource()==b1) 
sign(1); 
else if(e.getSource()==b2) 
sign(2); 
else if(e.getSource()==b3) 
sign(3); 
else if(e.getSource()==b4) 
sign(4); 
//等號 
else if(e.getSource()==f1){ 
str=resultField.getText(); 
if(str.indexOf(".")<=1){ 
str+="."; 
resultField.setText(str); 
} 
} 
else if(e.getSource()==f2){ 
num2=Double.parseDouble(resultField.getText()); 

if(add){ 
num1=num1 + num2;} 
else if(sub){ 
num1=num1 - num2;} 
else if(mul){ 
num1=num1 * num2;} 
else if(div){ 
num1=num1 / num2;} 
resultField.setText(String.valueOf(num1)); 
end=true; 
} 


} 
public void sign(int s){ 
if(s==1){ 
add=true; 
sub=false; 
mul=false; 
div=false; 
} 
else if(s==2){ 
add=false; 
sub=true; 
mul=false; 
div=false; 
} 
else if(s==3){ 
add=false; 
sub=false; 
mul=true; 
div=false; 
} 
else if(s==4){ 
add=false; 
sub=false; 
mul=false; 
div=true; 
} 
num1=Double.parseDouble(resultField.getText()); 
end=true; 
} 
public static void main(String[] args){ 
testZ th1=new testZ(); 
th1.show(); 
} 
}