sample006.ptuc

(*  Passing around functions  *)

program function_fun;

type
   intfunc = function(n: integer) : integer;
   string = array of char;

function fibonacci(n:integer) : integer;
var
	f0, f1, temp: integer;
begin
	f0:=0;
	f1:=1;
	while n>1 do
		begin
			temp := f1;
			f1 := f1+f0;
			f0 := temp;
			n := n-1
		end;
	result := f1
end;

function factorial(n:integer) : integer;
var
	fac, i: integer;
begin
	fac := 1; 
	for i:=n downto 1 do 
	  fac:=i*fac;
	result := fac;
	return
end;

procedure eval(prompt: string; f: intfunc; val: integer);
begin
	writeString(prompt); 
	writeString('('); writeInteger(val); writeString(')=');
	writeInteger(f(val));
	writeString('\n')
end;

begin
	eval('Fibonacci', fibonacci, 5);
	eval('factorial', factorial, 5)
end.