Chrono 편집하기 (부분)

==시간 변환과 형식화==

===시간 단위 변환===
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#include <iostream>
#include <chrono>

int main() {
    using namespace std::chrono;
    
    // 다양한 단위로 시간 생성
    auto ns = nanoseconds(1234567890);
    
    // 상위 단위로 변환
    auto ms = duration_cast<milliseconds>(ns);
    auto sec = duration_cast<seconds>(ns);
    
    std::cout << ns.count() << " 나노초는" << std::endl;
    std::cout << ms.count() << " 밀리초 또는" << std::endl;
    std::cout << sec.count() << " 초입니다." << std::endl;
    
    // 부동소수점 변환
    duration<double, std::milli> precise_ms = ns;
    std::cout << "정확한 밀리초: " << precise_ms.count() << "ms" << std::endl;
    
    return 0;
}
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===시간 형식화===
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#include <iostream>
#include <chrono>
#include <iomanip>
#include <sstream>

std::string format_duration(std::chrono::nanoseconds ns) {
    using namespace std::chrono;
    
    auto hours = duration_cast<std::chrono::hours>(ns);
    ns -= hours;
    auto minutes = duration_cast<std::chrono::minutes>(ns);
    ns -= minutes;
    auto seconds = duration_cast<std::chrono::seconds>(ns);
    ns -= seconds;
    auto milliseconds = duration_cast<std::chrono::milliseconds>(ns);
    
    std::stringstream ss;
    ss << std::setfill('0') << std::setw(2) << hours.count() << ":"
       << std::setw(2) << minutes.count() << ":"
       << std::setw(2) << seconds.count() << "."
       << std::setw(3) << milliseconds.count();
    
    return ss.str();
}

int main() {
    auto duration = std::chrono::nanoseconds(3723456789000); // 1시간 2분 3초 456ms
    std::cout << "형식화된 시간: " << format_duration(duration) << std::endl;
    
    return 0;
}
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