?- start. input a= 3. input b= 4. input c= 5. These numbers are the edges of a triangle. true.
start:- write('input a= '),read(A), write('input b= '),read(B), write('input c= '),read(C), A >= 0,B >= 0,C >= 0, /* must be positive */ A < B + C,B < C + A,C < A + B, write('These numbers are the edges of a triangle.').