怎么实现一个计算器

import java.awt.BorderLayout;import java.awt.Color;import java.awt.FlowLayout;import java.awt.Fontimport java.awt.GridLayout;import java.awt.event.ActionEvent;import java.awt.event.ActionListener; import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JPanel;import javax.swing.JTextArea; public class calculator implements ActionListener {  JFrame frame=new JFrame(); private JButton[] b; private JButton b2; private JTextArea t; private JButton jbtnsqrt; private boolean flag=false;  public calculator() {  jbtnsqrt=new JButton("Sqrt");  b=new JButton[16];  b2=new JButton("C");  String str="123+456-789x0.=/";  for(int i=0;i<b.length;i++){  b[i]=new JButton(str.substring(i,i+1));  }  } private void setFontAndColor(){  Font f=new Font("宋体",Font.BOLD,18);  t.setFont(f);  for(int i=0;i<b.length;i++){   b[i].setFont(f);  } } private void init(){  t=new JTextArea(1,20);  JPanel northPanel=new JPanel();  JPanel centerPanel=new JPanel();  northPanel.setLayout(new FlowLayout());  centerPanel.setLayout(new GridLayout(4,4));  northPanel.add(t);  northPanel.add(b2);  northPanel.add(jbtnsqrt);  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  b2.setBackground(Color.RED);  b2.setForeground(Color.green);  b2.addActionListener(this);     jbtnsqrt.addActionListener(this);  for(int i=0;i<b.length;i++){   centerPanel.add(b[i]);   b[i].addActionListener(this);   }  frame.setLayout(new BorderLayout());  frame.add(northPanel,BorderLayout.NORTH);  frame.add(centerPanel, BorderLayout.CENTER);  setFontAndColor();  frame.setLocation(340,300);  frame.setVisible(true);  frame.pack();  frame.setResizable(false);  }  public void actionPerformed(ActionEvent e) {  if(e.getSource()==b2) t.setText(null);//点击C时清空文本域  else if(e.getSource()==b[14]){     //点击=时读取文本域的字符串   String s=t.getText().trim();   String[] rs;   if(s.contains("+")){    rs=s.split("\\+");     double d=Double.parseDouble(rs[0])+Double.parseDouble(rs[1]);    t.setText(String.valueOf(d));   }   else if(s.contains("-")){    rs=s.split("-");    double d=Double.parseDouble(rs[0])-Double.parseDouble(rs[1]);    t.setText(String.valueOf(d));    }   else if(s.contains("x")){    rs=s.split("x");    double d=Double.parseDouble(rs[0])*Double.parseDouble(rs[1]);    t.setText(String.valueOf(d));   }   else if(s.contains("/")){    rs=s.split("/");    double d=Double.parseDouble(rs[0])/Double.parseDouble(rs[1]);    t.setText(String.valueOf(d));         }   flag=true;  }else if(e.getSource()==jbtnsqrt){   String s=t.getText().trim();   double d=Math.sqrt(Double.parseDouble(s));   t.setText(String.valueOf(d));   }  else {   if(flag){    t.setText("");   }//   不点击=和C时，将字符串追加在文本域中   t.append(e.getActionCommand());    flag=false;  }  } public static void main(String[] args) {  new calculator().init();  }}
switch 加上 while
<script type="text/javascript" src="tool/jquery-1.8.3.js"></script>
<script type="text/javascript">
$(function(){
$(":button").click(function (){
var a=$(this).attr("value");
if(a!="="){
$("#sj").val($("#sj").val()+a);
}else{
var a=$("#sj").val();
var v=eval(a);
$("#jg").val(v);
$("#sj").val("");
}
});
});
</script>
  </head>

  <body>
     <button  value="1">1</button>
     <button  value="2">2</button>
     <button  value="3">3</button><br>
     <button  value="4">4</button>
     <button  value="5">5</button>
     <button  value="6">6</button><br>
     <button  value="7">7</button>
     <button  value="8">8</button>
     <button  value="9">9</button><br>
     <button  value="0">0</button>
     <button  value="+">+</button>
     <button  value="-">-</button><br>
     <button  value="*">*</button>
     <button  value="/">/</button>
     <button  value="=">=</button><br>
     <input id="sj">=<input id="jg">
  </body>
用JQuery写的

调试易

怎么实现一个计算器

解决方案 »