C++使用chrono获取时间差

#include 
#include 

int main(){
	auto start = std::chrono::high_resolution_clock::now();
	int res = 1;
	for(int i=0; i<100000; i++){
		res++;
	}
	auto end = std::chrono::high_resolution_clock::now();
	std::chrono::duration<double, std::milli> tm = end - start;	// 毫秒
	// std::chrono::duration tm = end - start; 微秒
	std::cout << "time: " << tm.count() << "ms" << std::endl;
	return 0;
}