How to sum multiple results from a predicate in prolog?

问题

So I have a predicate that sometimes returns more than one numerical result, eg.

X=3;

X=1

How can I sum multiple return values together? On occasion my predicate returns a single numerical value which is fine but if it returns more than one I want it to sum the multiple results together and output that rather than listing them separately.

Thanks.

回答1:

You didnt show us code so i cant tell exactly what is correct solution, but you can try with findall/3 or bagof/3 predicates to collect results in list and then sum them all.

来源：https://stackoverflow.com/questions/35867950/how-to-sum-multiple-results-from-a-predicate-in-prolog