====== List sum ======
{{tag>arithmetic lists}}
===== Description =====
Determining the length of a list using stack. 

**Source**:  PROLOG str. 195 Wydawnictwo PLJ Warszawa 1991 ISBN 83-85190-63-5
===== Download =====
Program source code: {{list_sum.pl}}
===== Listing =====
<code prolog>
suma([], Sum, Sum, Ilosc, Ilosc).
suma([H|T], Sum, Sum1, Ilosc, Ilosc1) :- Nilosc is Ilosc + 1,
Nsuma is Sum1 + H, suma(T, Sum, Nsuma, Ilosc, Nilosc).

test :- suma([1, 2, 3, 4, 4, 5], S, 0, Ilosc, 0).</code>
===== Comments =====