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?

>>51
Not entirely sure what >>40 has in mind, but main's prototype typically has 2 arguments: argc and argv. Defining it with no arguments won't cause problems with most popular x86 C compilers as they use the cdecl calling convention (caller cleans the stack), which essentially means that you could define a function which uses that calling convention with less arguments and it won't corrupt anything or cause a crash (but a different calling convention might corrupt the stack).