std::difftime
From cppreference.com
| Defined in header <ctime>
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| double difftime( std::time_t time_end, std::time_t time_beg ); |
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Computes difference between two calendar times as std::time_t objects (time_end - time_beg) in seconds. If time_end refers to time point before time_beg then the result is negative.
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[edit] Parameters
| time_beg, time_end | - | times to compare |
[edit] Return value
Difference between two times in seconds.
[edit] Notes
On POSIX systems, std::time_t is measured in seconds, and difftime is equivalent to arithmetic subtraction, but C and C++ allow fractional units for time_t.
[edit] Example
Run this code
#include <iostream> #include <ctime> int main() { std::time_t start = std::time(NULL); volatile double d; // some time-consuming operation for (int n=0; n<10000; ++n) { for (int m=0; m<100000; ++m) { d += d*n*m; } } std::cout << "Wall time passed: " << std::difftime(std::time(NULL), start) << " s.\n"; }
Output:
Wall time passed: 7 s.
[edit] See also
| (C++11) |
a time interval (class template) |
| C documentation for difftime
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