references/C/11_memory.md

Memory

int i = 121313;

Tells the computer to put aside some memory for i, as an integer.

This is stored at a certain memory address.

%i;
printf("0x%p\n", &i);

The value will then be stored in that memory and can be referenced with the variable name, or with a pointer.

Pointers

Pointer's can reference a memory address, this is like a varialbe that stores a memory address;

int * p = &i;

int * p = 0;

Pointers set to 0 have no memory address, but should be declared as such instead of with no initialisation, as no init could cause bugs and other issues.

Derefferenced Pointers

Pointers can also be dereffernced to get the value being pointed to, istead of the memory address itself.

int j = *p;

j is a referrence of p's memory address, the actual value of the varialbe it's pointed to.

*p = 34234;

The derefferenced value of p can be altered, while keeping the same memory address through derefferencing.