static std::chrono::time_point<std::chrono::system_clock> now(); | (since C++11) |
Returns a time point representing the current point in time.
Parameters
(none).
Return value
A time point representing the current time.
Exceptions
noexcept
specification: noexcept
Example
#include <iostream> #include <vector> #include <numeric> #include <chrono> volatile int sink; int main() { for (auto size = 1ull; size < 1000000000ull; size *= 100) { // record start time auto start = std::chrono::system_clock::now(); // do some work std::vector<int> v(size, 42); sink = std::accumulate(v.begin(), v.end(), 0u); // make sure it's a side effect // record end time auto end = std::chrono::system_clock::now(); std::chrono::duration<double> diff = end-start; std::cout << "Time to fill and iterate a vector of " << size << " ints : " << diff.count() << " s\n"; } }
Possible output:
Time to fill and iterate a vector of 1 ints : 2.43e-07 s Time to fill and iterate a vector of 100 ints : 4.1e-07 s Time to fill and iterate a vector of 10000 ints : 2.519e-05 s Time to fill and iterate a vector of 1000000 ints : 0.00207669 s Time to fill and iterate a vector of 100000000 ints : 0.423087 s
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