handledownnumber.java

《Java课程设计》第二版

import java.util.LinkedList;
import javax.swing.*;
import java.awt.event.*;
public class HandleDownNumber implements ActionListener{
    LinkedList<String> list;
    JTextField resultShow,showComputerProcess;          
    JTextArea saveComputerProcess; 
    HandleDownNumber(LinkedList<String> list,JTextField t1,JTextField t2,
                    JTextArea t3){
        this.list=list;
        resultShow=t1;
        showComputerProcess=t2; 
        saveComputerProcess=t3;
    }
    public void actionPerformed(ActionEvent e){
       if(list.size()==1||list.size()==2){
           String numOne=list.getFirst();
           try{  double d=Double.parseDouble(numOne);
                 double result=1.0/d;
                 String str=String.valueOf(result);
                 list.set(0,str);
                 resultShow.setText(str);
                 String proccess="1/"+numOne+"="+result;
                 showComputerProcess.setText(proccess);
                 saveComputerProcess.append("\n"+proccess);
                 if(list.size()==2)
                    list.removeLast(); //移掉运算符号 
              }
           catch(Exception ee){}
       } 
       else if(list.size()==3){
           String numTwo=list.getLast();
           try{  double d=Double.parseDouble(numTwo);
                 double result=1.0/d;
                 String str=String.valueOf(result);
                 list.set(0,str);
                 resultShow.setText(str);
                 String proccess="1/"+numTwo+"="+result;
                 showComputerProcess.setText(proccess);
                 saveComputerProcess.append("\n"+proccess);
                 list.removeLast(); //移掉第2个运算数 
                 list.removeLast(); //移掉运算符号 
              }
           catch(Exception ee){}
        }
    }
}