C Memory Address

Memory Address

A memory address is a unique identifier assigned by the system to a specific location in memory. In C programming, each variable, array element, structure member, etc., occupies a certain amount of memory and is assigned a corresponding memory address.

Size: They can hold a large enough value to represent memory addresses on most systems.

Unsigned: Memory addresses are non-negative values, so using unsigned types avoids potential issues with signed integer behavior.

The actual size and representation of memory addresses can vary depending on the system architecture (32-bit vs. 64-bit) and platform.

To access it, use the reference operator (&), and the result represents where the variable is stored:

Example

#include <stdio.h>

int main() {

int myAge = 43;

printf("%p", &myAge);

return 0;

}

Output

0x7fff1cc65024

Note: Memory Addresses and Variables:

When a variable is declared in C, the system allocates a specific memory location to store the value of that variable. This memory location is identified by its unique memory address.

The memory address is represented in hexadecimal form using the prefix 0x followed by a combination of hexadecimal digits (0-9, A-F).

You should also note that &myAge is often called a "pointer". A pointer basically stores the memory address of a variable as its value. To print pointer values, we use the %p format specifier.

You will learn much more about pointers in the next chapter.

Why is it useful to know the memory address?

Pointers are important in C, because they allow us to manipulate the data in the computer's memory - this can reduce the code and improve the performance.

Pointers are one of the things that make C stand out from other programming languages, like Python and Java.