Each day do one impossible thing...
Consider:
void main() {
int a;
scanf("%d",&a);
while (a<
5) { a = a *1; }
}
If a<5 then this loops forever (does
not HALT)
Probably meant plus instead of times
(?)
Would it not be nice if we had a procedure
HALTS
int HALTS(program)
which would return 0 if any input
caused the program
to loop forever?
Or even if we had
int HALTS(program,input)
which would return 1 if program
is a valid program and
eventually halts when given input.