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?

>>126
Most of the code he writes that's over 5 lines usually have some kind of unintentional mistake in them, in the thread where he posted Java code he posted some nonsensical loops that didn't do what he said they were doing and he used that to argue against unordered collections. When prompted about it he of course just called the person who asked a mental midget even though the code was completely wrong.