The length of the code is actually not important.

A short question can contain reviewable code.

int main()
{
for(int i=0; i<=100000000000; i++); // <----- note that the loop doesn't do anything 
return 0;
}

We know what the author is trying to accomplish with this code. It accomplishes the intended task poorly, and we can say exactly why. That constitutes a good question.

The length of the code is actually not important.

A short question can contain reviewable code.

int main()
{
for(int i=0; i<=100000000000; i++); // <----- note that the loop doesn't do anything 
return 0;
}

We know what the author is trying to accomplish with this code. It accomplishes the intended task poorly, and we can say exactly why. That constitutes a good question.