Why doesn't my program crash when I write past the end of an array?

Question

Why does the code below work without any crash @ runtime ?

And also the size is completely dependent on machine/platform/compiler!!. I can even give upto 200 in a 64

Answer 1

That's undefined behavior - you simply don't observe any problems. The most likely reason is you overwrite an area of memory the program behavior doesn't depend on earlier - that memory is technically writable (stack size is about 1 megabyte in size in most cases) and you see no error indication. You shouldn't rely on this.