C++1y: Using user-defined literals for making `std::chrono::duration`s

example.cpp

#include <chrono>

constexpr auto operator "" _days (unsigned long long n) { return std::chrono::hours(24 * n); }
constexpr auto operator "" _h    (unsigned long long n) { return std::chrono::hours(n); }
constexpr auto operator "" _min  (unsigned long long n) { return std::chrono::minutes(n); }
constexpr auto operator "" _s    (unsigned long long n) { return std::chrono::seconds(n); }
constexpr auto operator "" _ms   (unsigned long long n) { return std::chrono::milliseconds(n); }
constexpr auto operator "" _µs   (unsigned long long n) { return std::chrono::microseconds(n); }
constexpr auto operator "" _ns   (unsigned long long n) { return std::chrono::nanoseconds(n); }

// ...

#include <iostream>
#include <thread>

int main() {
    auto t0 = std::chrono::steady_clock::now();
    std::cout << "Hello." << std::endl;
    std::this_thread::sleep_for(1_s + 500_ms);
    std::cout << "Still here." << std::endl;
    std::this_thread::sleep_for(3 * 500_ms);
    std::cout << "Bye." << std::endl;
    auto t1 = std::chrono::steady_clock::now();
    std::cout << "(That took " << (t1 - t0) / 1_ns << " nanoseconds.)" << std::endl;
}

Use "\n" instead of "std::endl" to avoid superfluous flushing of the output stream.