Factorial

Functions are often useful for calculating mathematical equations

Many mathematical functions are expressed recursively. Recursive functions are a natural programming mechanism in such cases.

Problem: multiply the numbers from 1 to N

N! ("N factorial") = 1 x 2 x 3 x ... x N

fact(n) =	n * fact (n-1)	{n>1}
	1	{n=1}

Code

	function factorial (n: in integer) return integer is
	begin
		if (n=1) then return 1;
		end if;
		return n * factorial(n-1);
	end;