implement: std::chrono::nanoseconds elapsed_time(uint64_t num_cpu_ticks); 1 2 3 4 8Example: “CPU ticks” time units constexpr uint64_t CPU_CLOCK_HZ = 400'000'000; // API to implement: std::chrono::nanoseconds num_cpu_ticks); 1 2 3 4 std::chrono::nanoseconds elapsed_time(uint64_t num_cpu_ticks) { using NS_PER_TICK = std::ratio<1'000'000'000, CPU_CLOCK_HZ>; return std::chrono::nanoseconds{ num_cpu_ticks uint64_t CPU_CLOCK_HZ = 400'000'000; // API to implement: std::chrono::nanoseconds elapsed_time(uint64_t num_cpu_ticks); 1 2 3 4 std::chrono::nanoseconds elapsed_time(uint64_t num_cpu_ticks) { using

0_C ; // floating point UDL IPv4Addr loopback = "127.0.0.1"_IPv4; // string UDL std::chrono::hours half_day = 12h ; // integer UDL const std::string greeting = "hello"s ; 2i; // complex(5.0, -3.2)Chrono duration UDLs ■ In sub-namespace chrono_literals: ■ Namespace std::chrono::chrono_literals is an alias for std::literals::chrono_literals. 10/26/21 Pablo Halpern literal type h chrono::hours Appropriate floating-point instantiation of chrono::duration min chrono::minutes s chrono::seconds ms chrono::milliseconds us chrono::microseconds ns chrono::nanoseconds

} 49 . 1TESTING WITH MORE TYPES TESTING WITH MORE TYPES using namespace std::chrono_literals; std::vectorchrono::seconds> v = {0s, 1s, 2s, 3s, 5s}; assert(min_absent(std::begin(v), std::end(v)) 4s); 50 . 1TESTING WITH MORE TYPES TESTING WITH MORE TYPES using namespace std::chrono_literals; std::vectorchrono::seconds> v = {0s, 1s, 2s, 3s, 5s}; assert(min_absent(std::begin(v), std::end(v)) EVEN MORE TYPES using namespace std::chrono_literals; using T = std::chrono::time_pointchrono::system_clock, std::chrono::seconds>; std::vector v = {T{0s}, T{1s}

(4. * min + 40. * s) / km; const quantity ttg = time_to_goal(half_marathon_distance, pace); std::chrono::seconds seconds = value_cast(ttg); std::println("Expected race time {:%T}" (4. * min + 40. * s) / km; const quantity ttg = time_to_goal(half_marathon_distance, pace); std::chrono::seconds seconds = value_cast(ttg); std::println("Expected race time {:%T}" * min + 40. * s) / km; const quantity ttg = time_to_goal(half_marathon_distance, 1 / pace); std::chrono::seconds seconds = value_cast(ttg); std::println("Expected race time {:%T}"

，KI::get_num_ joints()>::Random(); fk_interface::ForwardKinematicsInterface fk_interfacei start = std::chrono::high_resotution_ctock::now(); (int k = 9; k < muttiptiery kt+) { (int = 9; < iterations; i++r) { vatues[il); fk_interface.forward kinematics(); stop = std::chrono: :high_resotution_ ctocks:now(); duration = std::chrono::duration_castchrono::nanoseconds>(stop - start); cout << ts()>::Random(); fk_interface: :ForwardkinematicsInterface fk_interface; auto start = std::chrono::high_resotution_ ctock::now(); for (int k = 9; k < muttiptiery kt+) { for (int 1 = 69; 1< iterations;

// #include , <chrono>, template auto test(F f, Args &&... args) { using namespace std; using namespace std::chrono; auto pre = high_r attack(hero, *p); return victims.size(); // whatever }); using namespace std::chrono; std::print("Attacking {} victims {} times in {}", std::size(victims), M, durat attack(hero, *p); return victims.size(); // whatever }); using namespace std::chrono; std::print("Attacking {} victims {} times in {}", std::size(victims), M, durat

~INT() {} }; 46Libraries that wrap integers ● Smart pointers similarly wrap raw pointers ● std::chrono ● All other units libraries ● Safe integers ● Bindings for other languages 47Wrapper over int the popular libraries, right?std::chrono #include <chrono> int64_t int_seconds() { return 60; } std::chrono::seconds chrono_seconds() { return std::chrono::seconds{60}; } static_assert( static_assert(std::is_same_vchrono::seconds::rep>); 65 https://godbolt.org/z/E5e1nGY94armv8-a clang 18.1.0 x86-64 gcc 14.2 x64 msvc v19.40 VS17.10 mov w0, #60 ret mov eax, 60 ret mov eax, 60

before the read.Example of a data race on an int using SC = std::chrono::steady_clock; auto deadline = SC::now() + std::chrono::seconds(10); int counter = 0; std::thread threadB = std::thread([&](){ program has UB.Fixing the race via std::atomic using SC = std::chrono::steady_clock; auto deadline = SC::now() + std::chrono::seconds(10); std::atomic counter = 0; std::thread threadB

'\n'; token.schedule();}); workContract.schedule(); std::this_thread::sleep_for(std::chrono::seconds(10));Work Contract: Adding Threading 13 3 work_contract_group workContractGroup; '\n'; token.schedule();}); workContract.schedule(); std::this_thread::sleep_for(std::chrono::seconds(10));Work Contract: Adding Threading 13 4 work_contract_group workContractGroup; '\n'; token.schedule();}); workContract.schedule(); std::this_thread::sleep_for(std::chrono::seconds(10));Work Contract: Adding Threading 13 5 work_contract_group workContractGroup;

Concurrency Function Arguments and Return ValuesPerformance Comparison std::chrono::duration st = std::chrono::system_clock::now(); for (long long i = 0 ; i < 100000000; ++i) { int* tmp(new std::shared_ptr tmp(new int(i)); // std::shared_ptr tmp = std::make_shared(i); } auto dur=std::chrono::system_clock::now() - st(); std::cout << dur.count(); Pointer Time Available Since new 2.93