.gitignore

*.class

dentaku.java

import java.applet.*;
import java.awt.*;
import java.util.*;

public class dentaku extends Applet
{
    dentakuKeisan Keisan = new dentakuKeisan();	
    public void init(){
        setLayout(new BorderLayout());	
        Panel PA = new Panel();	
        PA.setLayout(new GridLayout(5,5,5,5));	
        Button B = new Button();	
        Font f = new Font("TimesRoman",Font.ITALIC,15);
        B.setFont(f);	
        B.setBackground(Color.lightGray);	
        B.setForeground(Color.red);

        PA.add(B = new Button("7"));	
        PA.add(B = new Button("8"));
        PA.add(B = new Button("9"));
        PA.add(B = new Button("/"));
        PA.add(B = new Button("4"));
        PA.add(B = new Button("5"));
        PA.add(B = new Button("6"));
        PA.add(B = new Button("*"));
        PA.add(B = new Button("1"));
        PA.add(B = new Button("2"));
        PA.add(B = new Button("3"));
        PA.add(B = new Button("-"));
        PA.add(B = new Button("."));
        PA.add(B = new Button("0"));
        PA.add(B = new Button("+/-"));
        PA.add(B = new Button("+"));
        PA.add(B = new Button("C"));
        PA.add(B = new Button("="));
        PA.add(B = new Button("("));
        PA.add(B = new Button(")"));

        add("North",Keisan);	
        add("Center",PA);
    }

    public boolean action(Event ev,Object arg){
        if(ev.target instanceof Button){	
            String la = (String)arg;	
            if(la.equals("C")){	
                Keisan.Clear();	
                return true;
            }else if(la.equals(".")){
                Keisan.Ten();
                return true;
            }else if(la.equals("+")){
                Keisan.Sisoku();
                Keisan.n = 1;	
                return true;
            }else if(la.equals("-")){
                Keisan.Sisoku();
                Keisan.n = 2;
                return true;
            }else if(la.equals("*")){
                Keisan.Sisoku();
                Keisan.n = 3;
                return true;
            }else if(la.equals("/")){
                Keisan.Sisoku();
                Keisan.n = 4;
                return true;
            }else if(la.equals("+/-")){	
                Keisan.Hanten();
                return true;
            }else if(la.equals("=")){
                Keisan.Dewa();
                return true;
            }
            else{	
                Keisan.Suji(la);
                return true;
            }
        }
        return false;
    }
}

class dentakuKeisan extends Panel	
{
    Label LA = new Label(" 0");	
    String s = " 0";	
    double total = 0;	
    String totals;	
    public int n = 0;	

    dentakuKeisan(){	
        setBackground(Color.yellow);	
        setFont(new Font("TimesRoman",Font.BOLD + Font.ITALIC,20));
        LA.setBackground(Color.white);	
        LA.setAlignment(1);	
        add("Center",LA);	
    }

    void Suji(String su){	
        s = s + su;	
        if(s.length() == 2 && s.charAt(0) == '0' && s.charAt(1) != '.'){

            s = s.substring(1);	
        }
        LA.setText(s);	
    }

    void Hanten(){	
        if(s.length() == 0)return;	
        if(s.charAt(0) == '-')s = s.substring(1);	
        else s = "-" + s;	
        LA.setText(s);
    }



    void Ten(){	
        if(s.indexOf('.') != -1){	
            return;
        }else{
            s = s + ".";
        }
        LA.setText(s);
    }

    void Sisoku(){	
        if(s.length() == 0)return;

        Double d = Double.valueOf(s);	
        switch(n){
        case 1:	
            total = total + d.doubleValue();
            break;
        case 2:	
            total = total - d.doubleValue();
            break;
        case 3:	
            total = total * d.doubleValue();
            break;
        case 4:	
            total = total / d.doubleValue();
            break;
        default:	
            total = d.doubleValue();
            break;
        }
        totals = new Double(total).toString();	
        LA.setText(totals);
        s = "0";
    }

    void Dewa(){	
        if(s.length() == 0)return;

        Double d = Double.valueOf(s);
        switch(n){
        case 1:
            total = total + d.doubleValue();
            break;
        case 2:
            total = total - d.doubleValue();
            break;
        case 3:
            total = total * d.doubleValue();
            break;
        case 4:
            total = total / d.doubleValue();
            break;
        default:
            total = d.doubleValue();
            break;
        }
        totals = new Double(total).toString();
        LA.setText(totals);
        s = "0";
    }

    void Clear(){	
        total = 0;	
        n = 0;	
        s = "0";
        LA.setText(s);
    }
}

index.html

<body>
<applet code="dentaku.class" width="800" height="400"></applet>
</body>

Makefile

Base = dentaku
JAVAC_Opts = -encoding utf8 -Xlint:unchecked -Xlint:deprecation
JAVA_Opts = -Dfile.encoding=UTF8
APV_Opts = 

default : do

build : $(Base).class

$(Base).class : $(Base).java
	javac $(JAVAC_Opts) $(Base).java 2>&1 | lv -Ou | cat

do : build
	appletviewer $(APV_Opts) index.html

test : build
	prove ./test.pl

clean :
	rm -rf *.class