Program won't crash when it should

(GCC C)
I ran a pointer over each member of an integer array, storing one character of input in each cell.

The program seems to consistently crash when I try to store X+3 or more characters, where X is the size of the array, but if I do not exceed X+2 it will not crash.

Why does it crashes exactly at the point it does, but not for X+1 or X+2?

Kodak has decent programming knowledge but lacks the intelligence to properly use it, as evident by the mathematics thread where he showed his incompetence when it came to mathematical clarity and thought. He made several poor attempts at defining some concepts mathematically and he even attempted to argue against a mathematically proven statement disregarding the simple proofs given in the thread itself presumably because he didn't understand them. If a person isn't intelligent enough to intuitively grasp what a subset is after reading the definition and seeing a couple of simple examples then he's most likely not very bright. He even started to mix the empty set into the definition as if it made any difference.