c/c++ tricks

auto __start = std::chrono::high_resolution_clock::now();

std::cout << __LINE__ << "L	elapsed=" << std::chrono::duration_cast<std::chrono::nanoseconds>((std::chrono::high_resolution_clock::now() - __start)).count() << "ns" << std::endl;
// printf("%uL	elapsed=%lldns
", __LINE__, std::chrono::duration_cast<std::chrono::nanoseconds>((std::chrono::high_resolution_clock::now() - __start)).count());

struct timeval __start, __end;gettimeofday(&__start, NULL);

gettimeofday(&__end, NULL), printf("%uL	elapsed=%ldus
", __LINE__, 1000000 * (__end.tv_sec - __start.tv_sec) + __end.tv_usec - __start.tv_usec);