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

public class Calculator extends Applet
{
	TextArea screen;
	Button one, two, three, four, five, six, seven, eight, nine, zero,
		div, mult, sub, ad, eq, clear;
	int total, num, lastnum;
	String st, st1;
	char oper;
	boolean operon=false;

	public Calculator()
	{
	}

	public String getAppletInfo()
	{
		return "Name: Calculator\r\n" +
		       "Author: Brian Jahns\r\n" +
		       "Created with Microsoft Visual J++ Version 1.1";
	}


	public void init()
	{
    	resize(100, 150);
		setBackground(Color.gray);
		
		screen=new TextArea("",1,12);
		add(screen);

		one=new Button("1");
		two=new Button("2");
		three=new Button("3");
		four=new Button("4");
		five=new Button("5");
		six=new Button("6");
		seven=new Button("7");
		eight=new Button("8");
		nine=new Button("9");
		zero=new Button("0");
		div=new Button("/");
		mult=new Button("*");
		sub=new Button("-");
		ad=new Button("+");
		eq=new Button("=");
		clear=new Button("c");
		add(seven);
		add(eight);
		add(nine);
		add(div);
		add(four);
		add(five);
		add(six);
		add(mult);
		add(one);
		add(two);
		add(three);
		add(sub);
		add(clear);
		add(zero);
		add(eq);
		add(ad);
	}

	public void destroy()
	{
	}

	public void paint(Graphics g)
	{
	}

	public void start()
	{
	}
	
	public void stop()
	{
	}

	public boolean action(Event evt, Object arg)
	{
		if(evt.target instanceof Button)
		{
			if(evt.target==one)
			{
				if(operon==false)
				{
					screen.appendText("1");
					return true;
				}
				else
				{
					screen.setText("1");
					operon=false;
					return true;
				}
			}
			else if(evt.target==two)
			{
				if(operon==false)
				{
					screen.appendText("2");
					return true;
				}
				else
				{
					screen.setText("2");
					operon=false;
					return true;
				}
			}
			else if(evt.target==three)
			{
				if(operon==false)
				{
					screen.appendText("3");
					return true;
				}
				else
				{
					screen.setText("3");
					operon=false;
					return true;
				}
			}
			else if(evt.target==four)
			{
				if(operon==false)
				{
					screen.appendText("4");
					return true;
				}
				else
				{
					screen.setText("4");
					operon=false;
					return true;
				}
			}
			else if(evt.target==five)
			{
				if(operon==false)
				{
					screen.appendText("5");
					return true;
				}
				else
				{
					screen.setText("5");
					operon=false;
					return true;
				}
			}
			else if(evt.target==six)
			{
				if(operon==false)
				{
					screen.appendText("6");
					return true;
				}
				else
				{
					screen.setText("6");
					operon=false;
					return true;
				}
			}
			else if(evt.target==seven)
			{
				if(operon==false)
				{
					screen.appendText("7");
					return true;
				}
				else
				{
					screen.setText("7");
					operon=false;
					return true;
				}
			}
			else if(evt.target==eight)
			{
				if(operon==false)
				{
					screen.appendText("8");
					return true;
				}
				else
				{
					screen.setText("8");
					operon=false;
					return true;
				}
			}
			else if(evt.target==nine)
			{
				if(operon==false)
				{
					screen.appendText("9");
					return true;
				}
				else
				{
					screen.setText("9");
					operon=false;
					return true;
				}
			}
			else if(evt.target==zero)
			{
				if(operon==false)
				{
					screen.appendText("0");
					return true;
				}
				else
				{
					screen.setText("0");
					operon=false;
					return true;
				}
			}
			else if(evt.target==div)
			{
				oper='/';
				st=screen.getText();
				lastnum=Integer.parseInt(st);
				operon=true;
			}
			else if(evt.target==mult)
			{
				oper='*';
				st=screen.getText();
				lastnum=Integer.parseInt(st);
				operon=true;
			}
			else if(evt.target==sub)
			{
				oper='-';
				st=screen.getText();
				lastnum=Integer.parseInt(st);
				operon=true;
			}
			else if(evt.target==ad)
			{
				oper='+';
				st=screen.getText();
				lastnum=Integer.parseInt(st);
				operon=true;
			}
			else if(evt.target==clear)
			{
				screen.setText("");
				total=0;
			}
			else //eq
			{
				if(oper == '/')
				{
					st=screen.getText();
					num=Integer.parseInt(st);
					total=lastnum/num;
				}
				else if(oper == '*')
				{
					st=screen.getText();
					num=Integer.parseInt(st);
					total=lastnum*num;
				}
				else if(oper == '-')
				{
					st=screen.getText();
					num=Integer.parseInt(st);
					total=lastnum-num;
				}
				else if(oper == '+')
				{
					st=screen.getText();
					num=Integer.parseInt(st);
					total=lastnum+num;
				}
				st1=Integer.toString(total);
				screen.setText(st1);
				lastnum=0;
				oper='!';
				operon=true;
			}
		}
		return true;
	}
}