pointer in c++

Question

How much can a C++ pointer navigate memory? What happens if we occupy memory cells with numbers using a loop, does data ruin other running apps?

Answer 1

Nope.
You can only access memory allocated to your program, any attempt to access not allowed memory cell will result in runtime error (segmentation fault) .

edit : though a pointer can still navigate across any legal memory address of the system, the problem comes when you try to access/write on a memory cell which is not allowed.