cin vs scanf

README.md

ubuntu 14.04, g++ 4.8

81.700000, 187.500000

ubuntu 14.04, clang++-3.8

76.400000, 186.800000

main.cc

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

typedef std::function<void()> Reader;

uint64_t bench(uint64_t iterations, const Reader& reader) {
	auto start = std::chrono::system_clock::now();

	for (uint64_t i = 0; i < iterations; i++) {
		reader();
	}

	auto end = std::chrono::system_clock::now();

	return std::chrono::duration_cast<std::chrono::milliseconds>(end -
	                                                             start)
	    .count();
}

int main() {
	uint64_t iter = 250000;
	uint64_t runs = 10;

	double t_scan = 0, t_cin = 0;

	for (uint64_t x = 0; x < runs; x++) {
		t_scan += bench(iter, []() {
			int64_t a = 0, b = 0, c = 0;
			scanf("%ld %ld %ld", &a, &b, &c);
		});

		t_cin += bench(iter, []() {
			int64_t a = 0, b = 0, c = 0;
			std::cin >> a >> b >> c;
		});
	}

	printf("%lf, %lf\n", t_scan / runs, t_cin / runs);
}