c++ milliseconds
Explanation of Measuring Time in Milliseconds in C++
To measure time in milliseconds in C++, you can use the std::chrono
library, which provides facilities for high-resolution time measurements. Here are the steps to measure time in milliseconds in C++:
Include the necessary header files: To use the
std::chrono
library, you need to include the<chrono>
header file.Create a
std::chrono::high_resolution_clock
object: This clock object provides a high-resolution time source. You can create an instance of this clock using thestd::chrono::high_resolution_clock
type.Capture the start time: Use the
now()
member function of the clock object to capture the current time as the start time. Assign this value to a variable of typestd::chrono::time_point
.Perform the task: Perform the task or operation for which you want to measure the time.
Capture the end time: Use the
now()
member function of the clock object again to capture the current time as the end time. Assign this value to another variable of typestd::chrono::time_point
.Calculate the duration: Subtract the start time from the end time to get the duration of the task. This will give you a value of type
std::chrono::duration
.Convert the duration to milliseconds: Use the
std::chrono::duration_cast
function to convert the duration to milliseconds. Pass the duration and thestd::chrono::milliseconds
type as template arguments to theduration_cast
function.Get the value in milliseconds: Access the value of the duration in milliseconds using the
count()
member function.
Here's an example code snippet that demonstrates these steps:
#include <iostream>
#include <chrono>
int main() {
// Step 2: Create a high_resolution_clock object
std::chrono::high_resolution_clock::time_point start_time, end_time;
// Step 3: Capture the start time
start_time = std::chrono::high_resolution_clock::now();
// Step 4: Perform the task
// ... Your code here ...
// Step 5: Capture the end time
end_time = std::chrono::high_resolution_clock::now();
// Step 6: Calculate the duration
std::chrono::duration<double, std::milli> duration = end_time - start_time;
// Step 7: Convert the duration to milliseconds
auto duration_ms = std::chrono::duration_cast<std::chrono::milliseconds>(duration);
// Step 8: Get the value in milliseconds
std::cout << "Duration: " << duration_ms.count() << " milliseconds" << std::endl;
return 0;
}
This code measures the duration of the task between the start and end times and prints the duration in milliseconds.
Please note that the std::chrono::high_resolution_clock
may not have nanosecond precision on all platforms, but it provides the highest available resolution. The actual resolution may vary depending on the system.