Pass By Reference vs. Pass By Value

• In C++ you can have a function with the following signature

void printList(list<int> &theList) {
  ...
}

This means that the variables theList is passed by reference, and it can be directly manipulated in memory. If & in not specified it is instead treated as pass by value, in which the whole object is copied.

Reference vs. Pointer

Feature	Reference Version	Pointer Version
How it’s passed	By reference (alias to the original object).	By pointer (memory address of the object).
Syntax in function	Use the argument directly.	Must dereference *arg to access the object.
Memory Safety	Cannot be null (references are always valid).	Can be null (requires explicit null-checks).
Reassignment	Cannot reassign the reference to another object.	Pointer can be reassigned to point to another object.
Performance	No overhead of copying or dereferencing.	Small overhead due to dereferencing.

Usage

• Reference operator is not available in C. It's a feature of C++
• C was designed to be simpler and more minimalistic, and references as an abstraction over pointers were introduced later in C++ for better syntax and safer memory handling.
• C relies on pointers for indirect referencing and memory manipulation.

int x = 10;

int &ref = x;   // ref is a reference to x
int *ptr = &x;  // ptr now holds the address of x