Define a recursive rule, in the form of
sum(Lst, Total), which can calculate the sum of a list of stated, where Lst is in the format of
[[s1, p1], [s2, p2], … [sn, pn]]
so i only want sum p and s is not numbers. how can i done this?
sum([[az, 7], [ca, 40], [ne, 3], [ut, 3], [or, 4],Total).
it should return
Total = 60. but my code is not returning anything
sum([[_,X]|T],Total) :- sum(T,Rest), Total is X + Rest.