新<chrono>
功能需要一点时间来适应,但是当您了解它们的工作原理时,它们会使事情变得相当容易。
您的问题可以像这样解决,例如:
#include <chrono>
#include <thread>
#include <iostream>
// for readability
using hr_clock = std::chrono::high_resolution_clock;
using hr_time_point = hr_clock::time_point;
using hr_duration = hr_clock::duration;
using milliseconds = std::chrono::milliseconds;
int main()
{
// note the program start time
hr_time_point prog_start = hr_clock::now();
// do stuff
std::this_thread::sleep_for(milliseconds(1000));
// find the duration
hr_duration d = hr_clock::now() - prog_start;
// cast the duration to milliseconds
milliseconds ms = std::chrono::duration_cast<milliseconds>(d);
// print out the number of milliseconds
std::cout << "time passed: " << ms.count() << " milliseconds.\n";
}
为方便起见,您可以创建一个函数来返回自上次调用该函数以来的时间:
milliseconds since_last_call()
{
// retain time between calls (static)
static hr_time_point previous = hr_clock::now();
// get current time
hr_time_point current = hr_clock::now();
// get the time difference between now and previous call to the function
milliseconds ms = std::chrono::duration_cast<milliseconds>(current - previous);
// store current time for next call
previous = current;
// return elapsed time in milliseconds
return ms;
}
int main()
{
since_last_call(); // initialize functions internal static time_point
// do stuff
std::this_thread::sleep_for(milliseconds(1000));
milliseconds ms = since_last_call();
// print out the number of milliseconds
std::cout << "time passed: " << ms.count() << " milliseconds.\n";
}