# Finding Factors

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#### DemonFTW

##### Programmer
Hi,

I need to write a rule to find all the factors of a given number, this is that i have so far:

Code:
``````% "divisible without remainder function"
dwr(X, M) :- 0 is X mod M.

factors_of(X):-
D is 1,
findfactors(X, D).

findfactors(X, D):-
D = X,
F is X / D,
write(F).

findfactors(X, D):-
D < X,
E is D + 1,
findfactors(X, E),
Factor is X / D,
dwr(X, D), <--------- This line
nl,
write(Factor).``````

Notice the marked line, if i have that line there it will fail as soon as it gets to a number which isn't a factor and not return me any results after X, but without that line it will returnX divided by all of the lower numbers.

Is there a way to make it skip the non-factor numbers and still return the factors without failing ?

Or is there a better way to do this ? (I have to do this using recursion).

Thanks.

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