VulnTech References vs Pointers | Learn C++

You met references in the Functions module. A reference is another name for an existing variable:

#include <iostream>
using namespace std;

int main() {
    int original = 10;
    int& nickname = original;     // nickname IS original
    nickname = 20;
    cout << original << "\n";
    return 0;
}

Output

Side by side

	Reference `int& r = x;`	Pointer `int* p = &x;`
Use the value	`r`	`*p`
Can be empty?	No – always refers to something	Yes – `nullptr`
Can switch to another variable?	No	Yes
Must be set when created?	Yes	No (but you should!)

Functions with pointer parameters

Both let a function change the caller's variable. With a pointer the caller passes an address:

#include <iostream>
using namespace std;

void doubleIt(int* n) {
    *n = *n * 2;
}

void tripleIt(int& n) {
    n = n * 3;
}

int main() {
    int value = 5;
    doubleIt(&value);           // pass the address
    cout << value << "\n";
    tripleIt(value);            // pass the variable itself
    cout << value << "\n";
    return 0;
}

Output

10
30

Remember: Prefer references – they are simpler and can't be null. Use pointers when something might be “nothing” (nullptr), or must point to different things over time.