profile_pow.cpp

#include <iostream>
#include <chrono>
#include <cmath>
#include <vector>

#define N 100000000

void pow(){
	double a = 2.0, b = 3.0, c = 0.0;

	for (long int i = 0; i < N; i++)
		c += std::pow(a, b);

	std::cout << c << std::endl;  // Side effect to avoid optimization
}

void explog(){
	double a = 2.0, b = 3.0, c = 0.0;

	for (long int i = 0; i < N; i++)
		c += std::exp(b * std::log(a));

	std::cout << c << std::endl;
}

int main()
{
	auto t1 = std::chrono::high_resolution_clock::now();
	pow();
	auto t2 = std::chrono::high_resolution_clock::now();
	auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(t2 - t1).count();

	printf("pow     : %d ms\n", duration);


	t1 = std::chrono::high_resolution_clock::now();
	explog();
	t2 = std::chrono::high_resolution_clock::now();
	duration = std::chrono::duration_cast<std::chrono::milliseconds>(t2 - t1).count();

	printf("exp(log) : %d ms.\n", duration);

	std::getchar();
}