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  1. countdown(X) :- number(X), X<0.
  2. countdown(X) :- number(X), X>=0, write(X), nl, NX is X - 1, countdown(NX).
  3. ?- countdown(4).
Compilation error #stdin compilation error #stdout 0s 0KB
comments (?)
stdin
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Standard input is empty
compilation info 
prog.pl:3:4: syntax error: . or operator expected after expression
	1 error(s)
compilation failed
stdout
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Standard output is empty
https://ideone.com/MD49t
language:
Prolog (gprolog 1.4.5)
created:
14 years ago
visibility:
public

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