lab6

implement main
    open core, console

class predicates
    fact : (real, real [out]).
clauses
    fact(N, 0) :-
        N < 1,
        !.
    fact(N, R) :-
        N1 = N - 1,
        fact(N1, R1),
        R = R1 + 1 / N.
    run() :-
        console::init(),
        fact(read(), R),
        write(R),
        nl.

end implement main

goal
    mainExe::run(main::run).