Passing Non-Const References to Overloaded Functions

When you pass a non-const variable (like a non-const int) to an overloaded function, and one overload takes a non-const reference (int&) while another takes a const reference (const int&), the compiler will prefer the non-const reference overload.

This is because binding a non-const reference to a non-const variable is considered an exact match, while binding a const reference to a non-const variable requires a trivial conversion (adding const).

Here's an example:

1#include <iostream>
2
3void Print(int& x) {
4  std::cout << "non-const ref overload";
5}
6
7void Print(const int& x) {
8  std::cout << "const ref overload";
9}
10
11int main() {
12  int x = 10;
13  Print(x);// calls Print(int&)
14}

1non-const ref overload

The output will be "non-const ref overload", because x is non-const and thus prefers the non-const reference overload.