[C++] ¿What is the difference between this expressions?

Question

I am at the dynamic memory part of C++, and I'm still quite confused about pointers.

I have 2 doubts/Questions.

CASE 1/Q 1:
Expression 1:
int * p;

Expression 2:
int *p;

¿Are they the same?
---------------------

CASE 2/Q 2:
Expression 1:
int * p;
p = 5;

Expression 2:
int * p;
*p = 5;

or

int *p;
*p = 5;

¿What does the pointer do when assigned with * here? ¿Whats the difference between asign with * and without *?

Answer 1

IIRC:

int * p, int* p and int *p is the same. They all declare a pointer p which can be used to store address of integer variables.

int *p; *p = 5; and int* p; p = 5; is not the same. A pointer stores the address of a variable. * (point-to) operator tells the program to point to the variable whose address is stored in the pointer. When we do p = 5; we store the value 5 into the pointer. When we do *p = 5; we store the value 5 into an integer variable whose address is stored in the pointer. E.g.

int x = 5; // integer variable x stores value 5.
int *p;

p = &x; // p now stores address of x. (& operator returns address of a variable)

std::cout << p; // print address of x.
std::cout << *p; // print value stored in x.

Answer 2

Try looking into this code written by ValentinHacker, it might help at getting to understand how & and * works.

https://code.sololearn.com/c7mW3DQoz3m0/?ref=app

Answer 3

Thanks Hatsy!