Measure elapsed time of a C++ program using Chrono library

This post will discuss how to measure the elapsed time of a C++ program in seconds, milliseconds, microseconds, and nanoseconds using the Chrono library.

Since C++11, the best way to measure elapsed time in C++ is by using the Chrono library, which deals with time.

Following C++ program calculates the time elapsed for a simple code in seconds, milliseconds, microseconds, and nanoseconds. It includes the <chrono.h> header which provides access to the current time using system_clock(). The system_clock is designed to represent the real-time and used by all processes running on the system.

#include <iostream>

#include <chrono>

#include <unistd.h>

using namespace std;

// Main function to measure elapsed time of a C++ program

// using Chrono library

int main()

{

auto start = chrono::steady_clock::now();

// do some stuff here

sleep(3);

auto end = chrono::steady_clock::now();

cout << "Elapsed time in nanoseconds: "

<< chrono::duration_cast<chrono::nanoseconds>(end - start).count()

<< " ns" << endl;

cout << "Elapsed time in microseconds: "

<< chrono::duration_cast<chrono::microseconds>(end - start).count()

<< " µs" << endl;

cout << "Elapsed time in milliseconds: "

<< chrono::duration_cast<chrono::milliseconds>(end - start).count()

<< " ms" << endl;

cout << "Elapsed time in seconds: "

<< chrono::duration_cast<chrono::seconds>(end - start).count()

<< " sec";

return 0;

}

Download Run Code

Output (may vary):

Elapsed time in nanoseconds: 3000090354 ns
Elapsed time in microseconds: 3000090 µs
Elapsed time in milliseconds: 3000 ms
Elapsed time in seconds: 3 sec

That’s all about measuring elapsed time of a C++ program using the Chrono library.

Related Post:

Find execution time of a C program