How do you pass by reference in C++ vs C?

C++ passes by reference with & parameters (void f(int& a)); C simulates it with pointers (void f(int* a)).

// C++ way (cleaner)
void swap(int& a, int& b) {
    int temp = a;
    a = b;
    b = temp;
}
swap(x, y);        // just pass the variables

// C way (explicit pointers)
void swap(int* a, int* b) {
    int temp = *a;
    *a = *b;
    *b = temp;
}
swap(&x, &y);      // must pass addresses

Advantages of references:

• Cleaner syntax at the call site (no & / * noise)
• Can't be null, so no null-check needed
• No pointer arithmetic possible, so less can go wrong

When to use pointers instead:

• The argument is optional (can be nullptr)
• You need to reseat what you point at
• Working with arrays or manual dynamic allocation