Question

1) to initialize a pointer I use:

int number, *Pnumber;
    Pnumber=&number;
    number=10;

Am I doing this right?

what about:

int *Pnumber;
*Pnumber=10;

When I compile it, I get:

RUN FAILED (exit value 1, total time: 858ms)

btw. do I need to use free(Pnumber) to free the memory?

Answer 1

Am I doing this right?

Yes, you are.

what about:

  `int *Pnumber;  
   *Pnumber=10;`

Pnumber is an unitialized pointer. Dereferencing this pointer leads to an undefined behavior. Pnumber must point to an allocated memory (either to a variable or a dynamically allocated memory area).

btw. do I need to use free(Pnumber) to free the memory?

As long as you don’t use malloc, don’t use free.