c++ 输出时间或者获取时间差

#include
usingnamespace std;
usingnamespace std::chrono;
classTimer
{
public:
    Timer() : m_begin(high_resolution_clock::now()) {}
    void reset() { m_begin = high_resolution_clock::now(); }
    //默认输出毫秒
    int64_t elapsed() const
    {
        return duration_cast(high_resolution_clock::now() - m_begin).count();
    }
    //微秒
    int64_t elapsed_micro() const
    {
        return duration_cast(high_resolution_clock::now() - m_begin).count();
    }
    //纳秒
    int64_t elapsed_nano() const
    {
        return duration_cast(high_resolution_clock::now() - m_begin).count();
    }
    //秒
    int64_t elapsed_seconds() const
    {
        return duration_cast(high_resolution_clock::now() - m_begin).count();
    }
    //分
    int64_t elapsed_minutes() const
    {
        return duration_cast(high_resolution_clock::now() - m_begin).count();
    }
    //时
    int64_t elapsed_hours() const
    {
        return duration_cast(high_resolution_clock::now() - m_begin).count();
    }
private:
    time_point m_begin;
};