C and C++ General

Concepts

Declaration

Contains the function signature to let the compiler know what the function is (name, return type, params type and count)

int sum(int a, int b)

int sum(int, int)

Definition

Contains the actual logic of the function. Can act as a [[#Declaration]] too, but need to be before calling it

int sum(int a, int b) {
	return a + b;
}

Memory, Variables

int x; // This doesn't initialise the variable. It's data is whatever the previous program used it for. DO NOT USE it before setting it to a value
int y = 0; // This initialises the variable.

In general practice it's ok (?) to not initialize a variable but do not use it before setting a value to it.

Keywords