'if' in prolog?

Question

Is there a way to do an if in prolog, e.g. if a variable is 0, then to do some actions (write text to the terminal). An else isn\'t even needed, but I can\'t find any docume

Answer 1

Prolog program actually is big condition for "if" with "then" which prints "Goal is reached" and "else" which prints "No sloutions was found". A, Bmeans "A is true and B is true", most of prolog systems will not try to satisfy "B" if "A" is not reachable (i.e. X=3, write('X is 3'),nl will print 'X is 3' when X=3, and will do nothing if X=2).