How can passing an argument by reference be implemented in C++?

In C++, passing an argument by reference allows the function to work with the original object rather than a copy. This is done by using an ampersand (&) after the parameter type in the function declaration.

Example of passing by reference:

void increment(int& value) {
    value += 1;  // modifies the original argument
}

int main() {
    int a = 5;
    increment(a);
    // now a == 6
    return 0;
}

This method is useful for:

• Avoiding copying large objects (efficiency).
• Modifying the passed data inside the function.

Important: When passing by reference, the function accesses the original object, so changes inside the function affect the argument in the call.