====== List length ======
{{tag>lists}}
===== Description =====
Determining the length of a list. 

**Source**:  PROLOG str. 52 Wydawnictwo PLJ Warszawa 1991 ISBN 83-85190-63-5
===== Download =====
Program source code: {{list_length.pl}}
===== Listing =====
<code prolog>
dlugosc([], 0).
dlugosc([G|O], N) :- dlugosc(O, N1), N is N1 + 1.</code>
===== Comments =====