How does using const references in C++ affect performance?

How does using const references in C++ affect performance?

Using const references in C++ can improve performance by avoiding unnecessary copies of large objects. When you pass an object as a const reference, the function can access the original object without creating a copy, which saves time and memory.

Are there any downsides to using const references?

Yes, one downside is that you cannot modify the object being referenced. If you need to change the object's state, you'll have to pass it by non-const reference or by value.

In what scenarios should I prefer const references?

You should prefer const references when passing large objects to functions, especially if you don't need to modify them. This is common with classes and structs.

Can you give an example of const reference usage?

Sure! Here's a simple example:

void printValue(const int& value) {
    std::cout << value << std::endl;
}

In this function, value is passed as a const reference, avoiding a copy.