求助编写计算器的问题

直接用好了int a,b,c;c=a+b;
c=a-b;
c=a*b;
c=a/b;
是不是被概念忽悠了...张口就类和接口...
这些基本的...系统默认类里面都带上了

饿晕我最近才开始学JAVA 很不懂。。基础太差了谢谢

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class MyCalculater extends JFrame implements ActionListener{JTextField tf=new JTextField();
String num="";
Double number;
int pointCount=0;char operation; JButton    b1=new JButton("1");
JButton    b2=new JButton("2");
JButton    b3=new JButton("3");
JButton    b4=new JButton("4");
JButton    b5=new JButton("5");
JButton    b6=new JButton("6");
JButton    b7=new JButton("7");
JButton    b8=new JButton("8");
JButton    b9=new JButton("9");
JButton    b0=new JButton("0");
JButton    b10=new JButton("+");
JButton    b11=new JButton("-");
JButton    b12=new JButton("*");
JButton    b13=new JButton("/");
JButton    b14=new JButton("=");
JButton    b15=new JButton(".");
JButton    b16=new JButton("<-");
JButton    b17=new JButton("S");
JButton    b18=new JButton("C");
JButton    b19=new JButton("+/-");void buildConstraints(GridBagConstraints gbc,int gx,int gy,
int gw,int gh,int wx,int wy){gbc.gridx=gx;
gbc.gridy=gy;
gbc.gridwidth=gw;
gbc.gridheight=gh;
gbc.weightx=wx;
gbc.weighty=wy;}
public  MyCalculater(){
super("MyCaculater");
setBounds(200,200,280,215);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false);GridBagLayout exlayout=new GridBagLayout();
GridBagConstraints constraints=new GridBagConstraints();
JPanel expane=new JPanel();
expane.setLayout(exlayout);
    b0.addActionListener(this);
b1.addActionListener(this);
b2.addActionListener(this);
    b3.addActionListener(this);
    b4.addActionListener(this);
b5.addActionListener(this);
    b6.addActionListener(this);
b7.addActionListener(this);
b8.addActionListener(this);
    b9.addActionListener(this);
    b10.addActionListener(this);
b11.addActionListener(this);
    b12.addActionListener(this);
b13.addActionListener(this);
b14.addActionListener(this);
    b15.addActionListener(this);
    b16.addActionListener(this);
b17.addActionListener(this);
    b18.addActionListener(this);
b19.addActionListener(this);GridLayout inlayout=new GridLayout(4,5,5,5);
JPanel inpane2=new JPanel();
inpane2.setLayout(inlayout);
inpane2.add(b1);
inpane2.add(b2);
inpane2.add(b3);
inpane2.add(b10);
inpane2.add(b18);
inpane2.add(b4);
inpane2.add(b5);
inpane2.add(b6);
inpane2.add(b11);
inpane2.add(b16);
inpane2.add(b7);
inpane2.add(b8);
inpane2.add(b9);
inpane2.add(b12);
inpane2.add(b19);
inpane2.add(b0);
inpane2.add(b15);
inpane2.add(b13);
inpane2.add(b17);
inpane2.add(b14);
    tf.setEditable(false);
    buildConstraints(constraints,0,0,1,1,100,20);
    constraints.fill=GridBagConstraints.HORIZONTAL;

    exlayout.setConstraints(tf,constraints);
    expane.add(tf);

    buildConstraints(constraints,0,1,1,1,100,80);
    exlayout.setConstraints(inpane2,constraints);


expane.add(inpane2);
setContentPane(expane);
setVisible(true);}
public void actionPerformed(ActionEvent event){
if(event.getSource()==b10){if(num!=""){// if num have not exact digital,then press +,-*/ button
   operation='+';
   number=new Double(num);
   num="";
   if(pointCount!=0)
     pointCount=0;


}
}

if(event.getSource()==b11){
if(num!=""){
operation='-';
   number=new Double(num);
   num="";
    if(pointCount!=0)
     pointCount=0;
}}

    if(event.getSource()==b12){
    if(num!=""){
    operation='*';
       number=new Double(num);
       num="";
        if(pointCount!=0)
     pointCount=0;
    }

    }

if(event.getSource()==b13){
if(num!=""){
operation='/';
   number=new Double(num);
   num="";
   if(pointCount!=0)
     pointCount=0;
}}


//number control
if(event.getSource()==b1){
num=num+'1';
tf.setText(num);}

if(event.getSource()==b2){
num=num+'2';
tf.setText(num);
}

if(event.getSource()==b3){
num=num+'3';
tf.setText(num);
}

if(event.getSource()==b4){
num=num+'4';
tf.setText(num);
}

if(event.getSource()==b5){
num=num+'5';
tf.setText(num);
}

if(event.getSource()==b6){
num=num+'6';
tf.setText(num);
}

if(event.getSource()==b7){
num=num+'7';
tf.setText(num);
}
if(event.getSource()==b8){
num=num+'8';
tf.setText(num);

}

if(event.getSource()==b9){
num=num+'9';
tf.setText(num);
}

if(event.getSource()==b0){
num=num+'0';
tf.setText(num);
}

if(event.getSource()==b15){
   if(pointCount==0){
     num=num+'.';
     pointCount++;
   }
   tf.setText(num);}
if(event.getSource()==b16){if(num.length()==1){num="";
tf.setText(num);
char n[]=num.toCharArray();
boolean pointExist=false;for(int i=0;i<=(num.length()-1);i++)
    {
   if(n[i]=='.')
   pointExist=true;
   break;
    }       if(pointExist==false)
       pointCount=0; }///////////////////
if(num.length()>1){num=num.substring(0,num.length()-1);
tf.setText(num);
char n[]=num.toCharArray();
boolean pointExist=false;for(int i=0;i<=(num.length()-1);i++)
    {
   if(n[i]=='.')
   pointExist=true;
   break;
    }       if(pointExist==false)
       pointCount=0; }///////////////////////////////
}
if(event.getSource()==b17){
if(num!=""){
  Double n=new Double(num);

    if(n.doubleValue()>=0){
double display=Math.sqrt(n.doubleValue());
num=""+display;
tf.setText(num);
    }
    else
    tf.setText("input error");
}


}
if(event.getSource()==b18){
num="0";pointCount=0;
tf.setText(num);}
if(event.getSource()==b19){
if(num!=""){    Double n=new Double(num);
    if(n.floatValue()>0){
    num="-"+n.doubleValue();
        tf.setText(num);
    }
    else {
    num=""+(-n.doubleValue());
    tf.setText(num);
    }


    }
    }
    if(event.getSource()==b14){
    double result;
    pointCount=1;//result is a float number with '.'
    switch (operation){
    case '+':if(num!=""){
         Double n1=new Double(num);
             result=n1.doubleValue()+number.doubleValue();
             num=""+result;
             tf.setText(""+result);
             operation='\0';
             number=new Double("0");
             n1=null;
             }
              break;
    case '-':if(num!=""){
             Double n2=new Double(num);
             result=number.doubleValue()-n2.doubleValue();
             num=""+result;
             tf.setText(""+result);
             operation='\0';
             number=new Double("0");
             n2=null;
             }

             break;

       case '*':if(num!=""){
               Double n3=new Double(num);
             result=number.doubleValue()*n3.doubleValue();
             num=""+result;
             tf.setText(""+result);
             operation='\0';
             number=new Double("0");
             n3=null;
                 }

             break;
       case '/':if(num!=""){
                 Double n4=new Double(num);
               if(n4.doubleValue()!=0){
             result=number.doubleValue()/n4.doubleValue();
                num=""+result;
               tf.setText(""+result);
               number=new Double("0");
               operation='\0';
                n4=null;
                }
                else{
             tf.setText("input error");
             n4=null;
                }
                 }
             break;


      default :    tf.setText(""+num);

    }
    }
  }// end actionPerformed()
public static void main(String[] s){MyCalculater calculater=new MyCalculater();}
}

先谢谢楼上的了，
不过好多地方看不懂
我现在在同学的指导下也做了点，不过只实现+   -  *   /    四个功能
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class NullLayout implements ActionListener
{
JFrame frame;
JTextField text;
public JButton    button_sqrt,button_plus,button_CE,button_cancel;
public JButton    button_7,button_8,button_9,button_chu;
public JButton    button_4,button_5,button_6,button_cheng;
public JButton    button_1,button_2,button_3,button_jian;
public JButton    button_0,button_dian,button_deng,button_jia;
public double     num1=0,num2=0;
public char       ch;
public NullLayout()
{

frame =new JFrame("计算器");
frame.setSize(250,160);
frame.setLocation(200,200);
frame.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});
frame.setLayout(null);
text=new JTextField();
text.setSize(400,20);
frame.getContentPane().add(text);
text.setLocation(0,0);
button_sqrt=new JButton("sqrt");
button_sqrt.setSize(60,20);
frame.getContentPane().add(button_sqrt);
button_sqrt.setLocation(0,20);
button_plus=new JButton("=/-");
button_plus.setSize(60,20);
frame.getContentPane().add(button_plus);
button_plus.setLocation(60,20);
button_CE=new JButton("CE");
button_CE.setSize(60,20);
frame.getContentPane().add(button_CE);
button_CE.setLocation(120,20);
button_cancel=new JButton("C");
button_cancel.setSize(60,20);
frame.getContentPane().add(button_cancel);
button_cancel.setLocation(180,20);
button_7=new JButton("7");
button_7.setSize(60,20);
frame.getContentPane().add(button_7);
button_7.setLocation(0,40);
button_8=new JButton("8");
button_8.setSize(60,20);
frame.getContentPane().add(button_8);
button_8.setLocation(60,40);
button_9=new JButton("9");
button_9.setSize(60,20);
frame.getContentPane().add(button_9);
button_9.setLocation(120,40);
button_chu=new JButton("/");
button_chu.setSize(60,20);
frame.getContentPane().add(button_chu);
button_chu.setLocation(180,40);
button_4=new JButton("4");
button_4.setSize(60,20);
frame.getContentPane().add(button_4);
button_4.setLocation(0,60);
button_5=new JButton("5");
button_5.setSize(60,20);
frame.getContentPane().add(button_5);
button_5.setLocation(60,60);
button_6=new JButton("6");
button_6.setSize(60,20);
frame.getContentPane().add(button_6);
button_6.setLocation(120,60);
button_cheng=new JButton("*");
button_cheng.setSize(60,20);
frame.getContentPane().add(button_cheng);
button_cheng.setLocation(180,60);
button_1=new JButton("1");
button_1.setSize(60,20);
frame.getContentPane().add(button_1);
button_1.setLocation(0,80);
button_2=new JButton("2");
button_2.setSize(60,20);
frame.getContentPane().add(button_2);
button_2.setLocation(60,80);
button_3=new JButton("3");
button_3.setSize(60,20);
frame.getContentPane().add(button_3);
button_3.setLocation(120,80);
button_jian=new JButton("-");
button_jian.setSize(60,20);
frame.getContentPane().add(button_jian);
button_jian.setLocation(180,80);
button_0=new JButton("0");
button_0.setSize(60,20);
frame.getContentPane().add(button_0);
button_0.setLocation(0,100);
button_dian=new JButton(".");
button_dian.setSize(60,20);
frame.getContentPane().add(button_dian);
button_dian.setLocation(60,100);
button_deng=new JButton("=");
button_deng.setSize(60,20);
frame.getContentPane().add(button_deng);
button_deng.setLocation(120,100);
button_jia=new JButton("+");
button_jia.setSize(60,20);
frame.getContentPane().add(button_jia);
button_jia.setLocation(180,100);
button_0.addActionListener(this);
button_1.addActionListener(this);
button_2.addActionListener(this);
button_3.addActionListener(this);
button_4.addActionListener(this);
button_5.addActionListener(this);
button_6.addActionListener(this);
button_7.addActionListener(this);
button_8.addActionListener(this);
button_9.addActionListener(this);
button_sqrt.addActionListener(this);
button_jia.addActionListener(this);
button_jian.addActionListener(this);
button_cheng.addActionListener(this);
button_chu.addActionListener(this);
button_dian.addActionListener(this);
button_deng.addActionListener(this);
button_plus.addActionListener(this);
button_cancel.addActionListener(this);
button_CE.addActionListener(this);
frame.setVisible(true);
frame.setResizable(false);
}
public void actionPerformed(ActionEvent e)
{
String com=e.getActionCommand();
if(e.getSource()==button_cancel)
  text.setText("");
else if(com.equals("+")||com.equals("-")||com.equals("*")||com.equals("/"))
{
try
{
num1=Double.valueOf(text.getText());
}
catch(Exception ee)
{
return;
}
ch=com.charAt(0);
text.setText("");
}
else if(e.getActionCommand().equals("="))
{
try{
num2=Double.valueOf(text.getText());
}
catch(Exception ee)
{
return;
}
if(ch=='+')num1=num1+num2;
else if(ch=='-')num1=num1-num2;
else if(ch=='*')num1=num1*num2;
else if(ch=='/')num1=num1/num2;
text.setText(""+num1);
}
else {
text.setText(text.getText()+e.getActionCommand());
}
}
public static void main(String args[])
{
new NullLayout();
}
}
新手希望大家多多帮忙哦

http://dreamerhx.ys168.com/myprogramming 我的程序
csdn_Express.rar 11KB CSDN帖子部分代码我以前讨论的表达式计算，希望能给大家帮助

qfs_v(眯眼眼光)能不能讲讲如何“工厂”做到？（了解一点工厂模式）

import java.awt.event.*;
import java.awt.*;
import javax.swing.*;
public class myCount extends JFrame implements ActionListener
{
JButton clear;
JTextField scanner;
mainBlock main;
frmdia dialog;
float floFont,floLast,floNum;
String strFont="";
String strLast="";
String strNum="";
String strSign="";
JPanel pane;
myCount()
{
super("计   算    器");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
dialog=new frmdia(this,"提示",true);
pane=new JPanel();
JPanel smlpane=new JPanel();
smlpane.setLayout(new GridLayout(2,1,20,20));
pane.setLayout(new GridLayout(2,1,0,10));
scanner=new JTextField("0",20);
scanner.setEditable(false);
clear=new JButton("清          零");
clear.addActionListener(this);
main=new mainBlock(this);
smlpane.add(scanner);
smlpane.add(clear);
pane.add(smlpane);
pane.add(main);
setContentPane(pane);
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==clear)
{
strSign="";
strLast="";strFont="";
scanner.setText("0");
floFont=0;
floLast=0;
repaint();
}
}
public static void main(String args[])
{
myCount mycount=new myCount();
mycount.pack();
}
public Insets getInsets()
{
return new Insets(40,15,25,15);
}
void others()
{
floFont=Float.parseFloat(strLast);
if(strSign=="+")
floNum=floLast+floFont;
else if(strSign=="-")
floNum=floLast-floFont;
else if(strSign=="*")
floNum=floLast*floFont;
else if(strSign=="/")
{
if(floFont==0)
{
dialog.setVisible(true);
strSign="";strNum="";
strLast="";strFont="";
scanner.setText("0");
floFont=0;
floLast=0;
floNum=0;
repaint();
}else{
floNum=floLast/floFont;
}
}
strLast=""+floNum;
strSign="";
}
void countNumber(mainBlock mblock,String str)
{
strNum=str;
if(strNum==".")
strNum="10";
else if(strNum=="=")
strNum="11";
else if(strNum=="+")
strNum="12";
else if(strNum=="-")
strNum="13";
else if(strNum=="*")
strNum="14";
else if(strNum=="/")
strNum="15";
int i=Integer.parseInt(strNum);
switch(i)
{
case 0:
case 1:
case 2:
case 3:
case 4:
case 5:
case 6:
case 7:
case 8:
case 9:
strLast+=(i);
break;
case 10:
strLast+=".";
break;
case 11:
if(strLast!="")
{
others();
}
break;
case 12:
if((strLast!="") && (strLast!="-"))
{
if(strSign!="")
{
others();
}
strSign="+";
floLast=Float.parseFloat(strLast);
strLast="";
}
break;
case 13:
if(strSign!="")
{
others();
}
strSign="-";
floLast=Float.parseFloat(strLast);
strLast="";
break;
case 14:
if((strLast!="") && (strLast!="-"))
{
if(strSign!="")
{
others();
}
strSign="*";
floLast=Float.parseFloat(strLast);
strLast="";
}
break;
case 15:
if((strLast!="") && (strLast!="-"))
{
if(strSign!="")
{
others();
}
strSign="/";
floLast=Float.parseFloat(strLast);
strLast="";
}
break;
}
scanner.setText(strLast);
pane.repaint();
}
}
class mainBlock extends JPanel implements ActionListener
{
myCount frame;
JButton[] btn=new JButton[16];
mainBlock(myCount parent)
{
frame=parent;
setLayout(new GridLayout(4,4,5,5));
for(int i=0;i<10;i++)
btn[i]=new JButton(""+i);
btn[10]=new JButton(".");
btn[11]=new JButton("=");
btn[12]=new JButton("+");
btn[13]=new JButton("-");
btn[14]=new JButton("*");
btn[15]=new JButton("/");
for(int i=0;i<16;i++)
{btn[i].addActionListener(this);}
add(btn[12]);
add(btn[13]);
add(btn[14]);
add(btn[15]);
for(int i=1;i<10;i++)
add(btn[i]);
add(btn[0]);
add(btn[10]);
add(btn[11]);
}
public void actionPerformed(ActionEvent e)
{
String str=e.getActionCommand();
frame.countNumber(this,str);
}
}
class frmdia extends Dialog implements ActionListener
{
Button btn;
Label lg;
frmdia(JFrame frm,String str,boolean b1)
{
super(frm,str,b1);
setBounds(200,250,95,110);
setVisible(false);
setLayout(null);
btn=new Button("确定");
lg=new Label("    错误参数");
add(lg);add(btn);
lg.setBounds(10,40,95,30);
btn.setBounds(30,70,40,25);
btn.addActionListener(this);
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
setVisible(false);
}
});
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==btn)
{
setVisible(false);
}
}
}

扫眼上面和下面的代码:
下面可以吗?请区别"=="和equals()!
strNum=str;
if(strNum==".")
strNum="10";
else if(strNum=="=")
strNum="11";
else if(strNum=="+")
strNum="12";
else if(strNum=="-")
strNum="13";
else if(strNum=="*")
strNum="14";
else if(strNum=="/")
strNum="15";

找了一段代码:注意他的事迹处理不完善!
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;public class Calculator
{
   public static void main(String[] args)
   {
      CalculatorFrame frame = new CalculatorFrame();
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.setVisible(true);
   }
}class CalculatorFrame extends JFrame
{
   public CalculatorFrame()
   {
      setTitle("Calculator");
      CalculatorPanel panel = new CalculatorPanel();
      add(panel);
      pack();
   }
}class CalculatorPanel extends JPanel
{
   public CalculatorPanel()
   {
      setLayout(new BorderLayout());      result = 0;
      lastCommand = "=";
      start = true;      display = new JButton("0");
      display.setEnabled(false);
      add(display, BorderLayout.NORTH);

      ActionListener insert = new InsertAction();
      ActionListener command = new CommandAction();      panel = new JPanel();
      panel.setLayout(new GridLayout(4, 4));      addButton("7", insert);
      addButton("8", insert);
      addButton("9", insert);
      addButton("/", command);      addButton("4", insert);
      addButton("5", insert);
      addButton("6", insert);
      addButton("*", command);      addButton("1", insert);
      addButton("2", insert);
      addButton("3", insert);
      addButton("-", command);      addButton("0", insert);
      addButton(".", insert);
      addButton("=", command);
      addButton("+", command);      add(panel, BorderLayout.CENTER);
   }   private void addButton(String label, ActionListener listener)
   {
      JButton button = new JButton(label);
      button.addActionListener(listener);
      panel.add(button);
   }   private class InsertAction implements ActionListener
   {
      public void actionPerformed(ActionEvent event)
      {
         String input = event.getActionCommand();
         if (start)
         {
            display.setText("");
            start = false;
         }
         display.setText(display.getText() + input);
      }
   }   private class CommandAction implements ActionListener
   {
      public void actionPerformed(ActionEvent event)
      {
         String command = event.getActionCommand();         if (start)
         {
            if (command.equals("-"))
            {
               display.setText(command);
               start = false;
            }
            else
               lastCommand = command;
         }
         else
         {
            calculate(Double.parseDouble(display.getText()));
            lastCommand = command;
            start = true;
         }
      }
   }   public void calculate(double x)
   {
      if (lastCommand.equals("+")) result += x;
      else if (lastCommand.equals("-")) result -= x;
      else if (lastCommand.equals("*")) result *= x;
      else if (lastCommand.equals("/")) result /= x;
      else if (lastCommand.equals("=")) result = x;
      display.setText("" + result);
   }

   private JButton display;
   private JPanel panel;
   private double result;
   private String lastCommand;
   private boolean start;
}

qfs_v(眯眼眼光)能不能讲讲如何“工厂”做到？（了解一点工厂模式）
----------------------
不好意思,概念性错误!对不起.让你误会了!

调试易

求助编写计算器的问题

解决方案 »