计算机

package ad;

import javax.swing.;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class c extends JFrame implements ActionListener
{
private String[] KEYS={"7","8","9","","4","5","6","-","1","2","3","+","0","÷","=",".","c"};
private JButton keys[]=new JButton[KEYS.length];
private JTextField resultText = new JTextField("0.0");
private String b="";
public c()
{
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.length;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.length; 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
    {
        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<str.length();i++)
    {
        if ("0123456789.".indexOf(str.charAt(i))>=0)
        {
            s="";
            for (;i<str.length()&&"0123456789.".indexOf(str.charAt(i))>=0;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);
                }
            }
           
        }
    }
    return Result[Top];
}
public static void main(String arg[])
{
    c a=new c();
}

}

来源：https://www.cnblogs.com/1786722420yang/p/11546939.html