====== List sum 3 ======
{{tag>lists arithmetic}}
===== Description =====
Iterative version of summing a list of integers using an accumulator. 

**Source**:  The Art of Prolog
===== Download =====
Program source code: {{list_sum_3.pl}}
===== Listing =====
<code prolog>
/*
   sumlist(Is,Sum) :- Sum is the sum of the list of integers Is.
*/
     sumlist(Is,Sum) :- sumlist(Is,0,Sum).

     sumlist([I|Is],Temp,Sum) :- 
	Temp1 is Temp+I, sumlist(Is,Temp1,Sum).
     sumlist([],Sum,Sum).

%  Program 8.6b   Iterative version of summing a list of integers
%					using an accumulator
</code>
===== Comments =====