How to Sleep for Milliseconds in C++?

In programming, sleeping for milliseconds means pausing the execution of the current thread for a specified number of milliseconds, it is often used in cases like creating delays, controlling the execution speed of a program, or simulating a time-consuming operation. In this article, we will learn how to sleep a program for milliseconds in C++.

Sleep for Milliseconds in C++

To sleep for milliseconds in C++, we can use the std::this_thread::sleep_for function. This function is like a C++ version of the sleep function from the <thread> library that takes a duration as an argument and pauses the execution of the current thread for that duration. We can specify the duration in milliseconds using the std::chrono::milliseconds function from the <chrono> library.

Syntax to Use std::this_thread::sleep_for Function

this_thread::sleep_for(chrono::milliseconds(duration));

Here, duration is the time in milliseconds for which you want to sleep.

C++ Program to Sleep for Milliseconds

The below program demonstrates how to make a program sleep for milliseconds in C++.

// C++ program to sleep for milliseconds

#include <chrono>
#include <iostream>
#include <thread>
using namespace std;

int main()
{
    // Print message indicating the start of program
    // execution.
    cout << "Execution Started.." << endl;

    // using for loop to print the interations
    for (int i = 0; i < 6; i++) {
        // Print the current loop counter value.
        cout << i << endl;

        // Check if the loop counter value is 3.
        if (i == 3) {
            // Print message indicating the program is about
            // to sleep.
            cout << "Sleeping for 5000 milliseconds..."
                 << endl;

            // Pause the program execution for 5000
            // milliseconds.
            this_thread::sleep_for(
                chrono::milliseconds(5000));

            // Print message indicating the program has
            // resumed after sleeping.
            cout << "Program Resumed" << endl;
        }
    }

    return 0;
}

Output

Execution Started..
0
1
2
3
Sleeping for 5000 milliseconds....
Program Resumed
4
5

Time Complexity: O(1)
Auxiliary Space: O(1)

Note: The std::this_thread::sleep_for and std::chrono::milliseconds functions are defined in the C++11 standard. So, these functions may not run with older compilers.