Windows.hを使った時間計測

QueryPerformanceCounter(&start);

//処理

QueryPerformanceCounter(&end);

#include <iostream>
#include <Windows.h>
int main() {
	LARGE_INTEGER freq;
	QueryPerformanceFrequency(&freq);

	LARGE_INTEGER start, end;

	QueryPerformanceCounter(&start);

	for (int i = 0; i <= 100; i++) {
		std::cout << "1";
	}
	std::cout << std::endl;
	QueryPerformanceCounter(&end);

	double time = static_cast<double>(end.QuadPart - start.QuadPart) * 1000.0 / freq.QuadPart;

	std::cout << "time ->" << time << "[ms]";

	return 0;
}