division2.java

完善的除法计算器

//源文件名：Division2.java
//在下载源程序中的文件夹：0803完善除法计算器
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class Division2 extends Applet implements TextListener
{
    Label prompt1,prompt2,prompt3;
    Label ExceptionMess,ExceptionMess1,ExceptionMess2;
    TextField input1,input2,output1,output2;
    int a,b,c,d;
    public void init()
    {
        input1=new TextField(5);
        prompt1=new Label("÷");
        prompt1.setAlignment(Label.CENTER);
        input2=new TextField(5);
        prompt2=new Label("＝");
        prompt2.setAlignment(Label.CENTER);
        output1=new TextField(5);
        prompt3=new Label("余");
        prompt3.setAlignment(Label.CENTER);
        output2=new TextField(5);
        ExceptionMess=new Label("                      ");
        ExceptionMess.setAlignment(Label.CENTER);
        ExceptionMess.setForeground(Color.red);
        ExceptionMess1=new Label("                                          ");
        ExceptionMess1.setAlignment(Label.CENTER);
        ExceptionMess1.setForeground(Color.blue);
        ExceptionMess2=new Label("                                            ");
        ExceptionMess2.setAlignment(Label.CENTER);
        ExceptionMess2.setForeground(Color.blue);
        add (input1);
        add (prompt1);
        add (input2);
        add (prompt2);
        add (output1);
        add (prompt3);
        add (output2);
        add (ExceptionMess);
        add (ExceptionMess1);
        add (ExceptionMess2);
        input1.addTextListener(this);
        input2.addTextListener(this);
        output1.setEditable(false);
        output2.setEditable(false);
    }
    public void textValueChanged(TextEvent e)
    {
        ExceptionMess.setText("");
        ExceptionMess1.setText("");
        ExceptionMess2.setText("");
        try
        {
            if (input1.getText().equals(""))
            {
                throw new Exception("被除数不能为空");
            }
            if (input1.getText().indexOf(".")>0)
            {
                throw new Exception("被除数不是整数");
            }
            if (input2.getText().indexOf(".")>0)
            {
                throw new Exception("除数不是整数");
            }
            a=Integer.parseInt(input1.getText());
            b=Integer.parseInt(input2.getText());
            c=a/b;
            d=a%b;
            output1.setText(Integer.toString(c));
            output2.setText(Integer.toString(d));
        }
        catch (ArithmeticException e1)
        {
            ExceptionMess.setText("除数不能为0,请重新输入");
            ExceptionMess1.setText(e1.getMessage());
            ExceptionMess2.setText(e1.toString());
            output1.setText("");
            output2.setText("");
        }
        catch(NumberFormatException e3)
        {
            ExceptionMess1.setText(e3.getMessage().equals("")?"除数不能为空":e3.getMessage()+"不是数字");
            output1.setText("");
            output2.setText("");
        }
        catch (Exception e2)
        {
            ExceptionMess1.setText(e2.getMessage());
            output1.setText("");
            output2.setText("");
        }
    }
}