std::function

#include <iostream>

class FunctionObj {
public:
	void operator() (int i) {
    	std::cout << "founctionObj" << i << std::endl;
    }
};

void freeFunction(int i) {
	std::cout << "freeFunction" << i << std::endl;
};

int main() {
	freeFunction(10);
    
    FunctionObj functionObj;
    functionObj(10);
    
    auto lambdaFn = [] (int i) {
    	std::cout << "lambdaFunction" << i << std::endl;
    }
    lambdaFn(10);
    
	return 0;
}