Functional Programming in Erlang_exercise 2.3

fibonacci_pieces.erl

-module fibonacci_pieces.
-export [test/0].
-export [fib/1].
-export [pieces/1].

test() ->
    0 = fibonacci_pieces:fib(1),
    5 = fibonacci_pieces:fib(6),
    1 = fibonacci_pieces:pieces(0),
    2 = fibonacci_pieces:pieces(1),
    7 = fibonacci_pieces:pieces(3),
    ok.
    
% @doc fib calculates the Nth Fibonacci number
    % Because the Fibonacci sequence requires two previous values, we must first establish those two base cases
    fib(1) ->
        0;
    fib(2) ->
        1;
    fib(N) when N>2 ->
        fib(N-1)+fib(N-2).

% @doc pieces calculates the maximum number of pieces into which a piece of paper can be cut with N straight lines.
% "Maximum" requires that each subsequent cut intersects every previous cut (i.e. never misses a previous cut nor
% intersects at a vertex), so the number of pieces is always increased by the number of cuts intersected.
    pieces(0) ->
        % the degenerate case of zero cuts is an important base case because it represents the default case
        % of the number of pieces in the entire original sheet of paper.
        1;
    pieces(N) when N>0 ->
        pieces(N-1) + N.

Indentation is a bit odd in this one, but the code is perfect.

Indentation is a bit odd in this one, but the code is perfect.

LOL, you're right. Learning Erlang at the same time I'm relearning Emacs. I still don't have everything set up quite right. Thank you for taking the time to review and comment.