c++11 direct function call, virtual function call, functor and std::function(using a lambda) performance test

functionperformance.cpp

#include <iostream>
#include <chrono>
#include <memory>
#include <functional>

using namespace std;
using namespace std::chrono;

class Base
{
public:
	Base() {}
	virtual ~Base() {}
	virtual int func(int i) = 0;
};

class Derived : public Base
{
public:
	Derived(int base = 10) : base{ base }
	{

	}
	~Derived() {}

	virtual int func(int i)
	{
		return i * base;
	}
private:
	int base;
};

struct Func
{
	int base;
	int operator()(int i)
	{
		return i * base;
	}
	Func(int base) : base{ base }
	{

	}
};

struct TestFunc
{
	int base = 1;

	int Call(int i)
	{
		return i * base;
	}
};
struct StdFunc
{
	std::function<int(int)> m_Func;
};

const int base = 10;
int calculate(int i)
{
	return base * i;
}

int main()
{
	const int num = 10000;
	Base* p = new Derived{ 10 };
	int total = 0;
	auto start = high_resolution_clock::now();
	for (int i = 0; i < num; ++i)
	{
		total += p->func(i);
	}
	auto end = high_resolution_clock::now();
	std::cout << "result: " << total << "\nvirtual call elapsed: \t" << duration_cast<nanoseconds>(end - start).count() << " nanoseconds.\n" << std::endl;

	total = 0;
	start = high_resolution_clock::now();
	for (int i = 0; i < num; ++i)
	{
		total += calculate(i);
	}
	end = high_resolution_clock::now();
	std::cout << "result: " << total << "\ndirect function call elapsed: \t" << duration_cast<nanoseconds>(end - start).count() << " nanoseconds.\n" << std::endl;

	Func functor{ 10 };
	total = 0;
	start = high_resolution_clock::now();
	for (int i = 0; i < num; ++i)
	{
		total += functor(i);
	}
	end = high_resolution_clock::now();
	std::cout << "result: " << total << "\nfunctor call elapsed: \t" << duration_cast<nanoseconds>(end - start).count() << " nanoseconds.\n" << std::endl;
	
	int base = 10;
	function<int(int)> lambda = [base](int i)
	{
		return i * base;
	};
	total = 0;
	start = high_resolution_clock::now();
	for (int i = 0; i < num; ++i)
	{
		total += lambda(i);
	}
	end = high_resolution_clock::now();
	std::cout << "result: " << total << "\nlambda call elapsed: \t" << duration_cast<nanoseconds>(end - start).count() << " nanoseconds.\n" << std::endl;
	return 0;
}