just example program that convert celcius to farenheit and vice versa

konverter.pas

{* Temperature Converter *}
{* Made by Yusuf Syaifudin *}
{* as request from Muhammad Angga Prasetyo - 2 December 2014 *}

program konverter;

{
	Formula to convert celsius to farenheit is:
	F = ((9/5)* C) +32
}
function celsiusToFarenheit(celsius: real): real;
	var
		(* local variable declaration *)
		result: real;
	begin
		result := ((9/5) * celsius) + 32;

		// Show 2 place before decimal point and 2 place after decimal point 
		writeln(celsius:2:2, ' celsius is equal to ',  result:2:2, ' farenheit' );

end;

{
	Formula to convert farenheit to celsius is:
	C=5/9 (F-32) 
}
function farenheitToCelsius(farenheit: real): real;
	var
		(* local variable declaration *)
		result: real;
	begin
		result := (5/9) * ( farenheit- 32);
		// Show 2 place before decimal point and 2 place after decimal point 
		writeln(farenheit:2:2, ' farenheit is equal to ',  result:2:2, ' celsius' )
end;


// main program
var
   a, b : real;

begin

	writeln('Welcome to Converter Progam.');
	writeln('==========================================');
	writeln('Select one menu');
	writeln('0. Exit program');
	writeln('1. Celsius to Farenheit');
	writeln('2. Farenheit to Celsius');

	// use READ instead of READLN, because it no more than one input
	read(a);


	if (a = 0) then
		exit
	else if (a > 2) then
		writeln('Wrong input!')
	else
		writeln('Input value: ');
		read(b);

		if  (a = 1) then
			celsiusToFarenheit(b)			

		else if (a = 2) then
			farenheitToCelsius(b)

		else
			writeln('No menu you select properly');

end.