Algorithm of the Applet

Main()
{
	Set the default function to zero
	instantiate M, X, C, default, User Inputs
	clear screen
	
	repeat {
		if ( action is addition ) then 
			add default function and the new function
			draw the new function
		else if ( action is substraction ) then
			substract the new function by the default function
			draw the new function
		else if ( action is multiplication) then
			multiply the default function and the new function
			draw the new function
		else if ( action is division ) then
			divide the default function by the new function
			draw the new function
		else if ( action is clear ) then
			set the default function to zero
			clear the screen
		else if ( action is Save as M ) then 
			set M function equal to the new function
		else if ( action is Save as C ) then
			set C function equal to the new function
		else if (action is Save as X ) then
			set X function equal to the new function
		else if (action is M ) then
			set the default function equal to function M
			draw M
		else if (action is C ) then
			set the default function equal to function C
			draw C
		else if (action is X ) then
			set the default function equal to function X
			draw X
		else if (action is Encode ) then
			result = create the transmitted signal X 
			set function X equal to result
			draw X
		else if (action is Decode) then
			result = recover the message from the transmitted signal
			draw the result
		else if ( action is Listen ) then
			sound player start playing ( the default function )
		else if ( action is Stop Listen) then
			sound player stop playing any sound
		else if ( action is Quit ) then
			the user quit this page and go to our main page
	until ( the action is Quit )
}