How can I use functors in C++ templates?

How can I use functors in C++ templates?

You can use functors in C++ templates by defining a class or struct with an overloaded operator(). This allows you to pass the functor as a template parameter.

Can you give me an example of a functor in a template?

Sure! Here's a simple example:

#include <iostream>

template <typename Func>
void applyFunction(Func f, int value) {
    std::cout << f(value) << std::endl;
}

struct Square {
    int operator()(int x) const { return x * x; }
};

int main() {
    Square square;
    applyFunction(square, 5); // Outputs 25
    return 0;
}

What are the benefits of using functors over regular functions?

Functors can maintain state, can be more flexible with parameters, and can be used with templates to create more generic and reusable code.

Are there any performance considerations when using functors?

Yes, functors can sometimes be more efficient than function pointers because they can be inlined by the compiler, reducing overhead.