What are functors in C++?

What are functors in C++?

Functors in C++ are objects that can be called as if they were functions. They are typically implemented by overloading the operator(). This allows you to create objects that can be used in a similar way to functions.

Can you give me an example of a functor?

Sure! Here's a simple example:

class Adder {
public:
    int operator()(int a, int b) {
        return a + b;
    }
};

int main() {
    Adder add;
    int result = add(5, 3); // result will be 8
}

What are the advantages of using functors?

Functors provide several advantages, such as:

1. They can maintain state between calls.
2. They can be passed as arguments to algorithms.
3. They can be more flexible than regular functions.

How do functors differ from function pointers?

Functors are objects and can hold state, while function pointers are just pointers to functions. Functors can also be more type-safe and can be overloaded.