实验代码：
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class Calculator extends JFrame implements ActionListener
{
private String[] KEYS={"7","8","9","*","4","5","6","-","1","2","3","+","0","e","π","÷","c","%",".","=","(",")","sqr","x*x"};
private JButton keys[]=new JButton[KEYS.length];
private JTextField resultText = new JTextField("0.0");
private String b="";
public Calculator()
{
super("计算器");
this.setLayout(null);
resultText.setBounds(20, 5, 255, 40);
resultText.setHorizontalAlignment(JTextField.RIGHT);
resultText.setEditable(false);
this.add(resultText);
int x=20,y=55;
for (int i=0;i
keys[i] = new JButton();
keys[i].setText(KEYS[i]);
keys[i].setBounds(x, y, 60, 40);
if(x<215)
{
x+=65;
}
else
{
x = 20;
y+=45;
}
this.add(keys[i]);
}
for (int i = 0; i
keys[i].addActionListener(this);
}
this.setResizable(false);
this.setBounds(500, 200, 300, 400);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.setVisible(true);
}
public void actionPerformed(ActionEvent e)
{
String label = e.getActionCommand();
if (label=="c"||label=="=")
{
if(label=="=")
{
String s[]=yunsuan(this.b);
String result=Result(s);
this.b=result+"";
resultText.setText(this.b);
}
else
{
this.b="";
resultText.setText("0");
}
}
else if (label=="sqr")
{
String n=yunsuan2(this.b);
resultText.setText(n);
this.b=n;
}
else if(label=="x*x")
{
String m=yunsuan3(this.b);
resultText.setText(m);
this.b=m;
}
else if(label=="e"||label=="π")
{
if (label=="e")
{
String m=String.valueOf(2.71828);
this.b=this.b+m;
resultText.setText(this.b);
}
if (label=="π")
{
String m=String.valueOf(3.14159265);
this.b=this.b+m;
resultText.setText(this.b);
}
}
else
{
this.b=this.b+label;
resultText.setText(this.b);
}
}
private String[] yunsuan(String str)
{
String s="";
char a[]=new char[100];
String jieguo[]=new String[100];
int top=-1,j=0;
for (int i=0;i
if ("0123456789.".indexOf(str.charAt(i))>=0)
{
s="";
for (;i
{
s=s+str.charAt(i);
}
i--;
jieguo[j]=s;
j++;
}
else if ("(".indexOf(str.charAt(i))>=0)
{
top++;
a[top]=str.charAt(i);
}
else if (")".indexOf(str.charAt(i))>=0)
{
for (;;)
{
if (a[top]!='(')
{
jieguo[j]=a[top]+"";
j++;
top--;
}
else
{
top--;
break;
}
}
}
else if ("*%÷".indexOf(str.charAt(i))>=0)
{
if (top==-1)
{
top++;
a[top]=str.charAt(i);
}
else
{
if ("*%÷".indexOf(a[top])>=0)
{
jieguo[j]=a[top]+"";
j++;
a[top]=str.charAt(i);
}
else if ("(".indexOf(a[top])>=0)
{
top++;
a[top]=str.charAt(i);
}
else if ("+-".indexOf(a[top])>=0)
{
top++;
a[top]=str.charAt(i);
}
}
}
else if ("+-".indexOf(str.charAt(i))>=0)
{
if (top==-1)
{
top++;
a[top]=str.charAt(i);
}
else
{
if ("%*÷".indexOf(a[top])>=0)
{
jieguo[j]=a[top]+"";
j++;
a[top]=str.charAt(i);
}
else if ("(".indexOf(a[top])>=0)
{
top++;
a[top]=str.charAt(i);
}
else if ("+-".indexOf(a[top])>=0)
{
jieguo[j]=a[top]+"";
j++;
a[top]=str.charAt(i);
}
}
}
}
for (;top!=-1;)
{
jieguo[j]=a[top]+"";
j++;
top--;
}
return jieguo;
}
public String yunsuan2(String str)
{
String result="";
double a=Double.parseDouble(str),b=0;
b=Math.sqrt(a);
result=String.valueOf(b);
return result;
}
public String yunsuan3(String str)
{
String result="";
double a=Double.parseDouble(str),b=0;
b=Math.pow(a, 2);
result=String.valueOf(b);
return result;
}
public String Result(String str[])
{
String Result[]=new String[100];
int Top=-1;
for (int i=0;str[i]!=null;i++)
{
if ("+-*%÷".indexOf(str[i])<0)
{
Top++;
Result[Top]=str[i];
}
if ("+-*%÷".indexOf(str[i])>=0)
{
double x,y,n;
x=Double.parseDouble(Result[Top]);
Top--;
y=Double.parseDouble(Result[Top]);
Top--;
if ("-".indexOf(str[i])>=0)
{
n=y-x;
Top++;
Result[Top]=String.valueOf(n);
}
if ("+".indexOf(str[i])>=0)
{
n=y+x;
Top++;
Result[Top]=String.valueOf(n);
}
if ("*".indexOf(str[i])>=0)
{
n=y*x;
Top++;
Result[Top]=String.valueOf(n);
}
if ("÷".indexOf(str[i])>=0)
{
if (x==0)
{
String s="ERROR";
return s;
}
else
{
n=y/x;
Top++;
Result[Top]=String.valueOf(n);
}
}
if ("%".indexOf(str[i])>=0)
{
if (x==0)
{
String s="ERROR";
return s;
}
else
{
n=y%x;
Top++;
Result[Top]=String.valueOf(n);
}
}
}
}
return Result[Top];
}
public static void main(String arg[])
{
Calculator a=new Calculator();
}
}
实验结果：
实验心得：
在该实验中，由于很多的不懂，缺乏上机的经验，对于该实验，简单的理论懂得，但不知道该如何编写程序，最后，在同学的帮助下完成了实验。