How to insert sleep/delay in a program?

Question

if I wrote a hello world program how to insert time in it ?
Like delay or sleep
please help me out in this..!!

Answer 1

You can use library called ctime. When you call its function time(NULL), it returns number of seconds from 1. 1. 1970. So your delay program could look like this:

#include <ctime>
using namespace std;

int main() {
// Your code before delay

// time_t is just data type for storing time, like int, double, string etc
time_t actual_time = time(NULL);

// time(NULL) in condition is changing every second, while actual_time is not changing, so it lasts 3 seconds while time(NULL) - actual_time > 3.
while(time(NULL) - actual_time < 3)
; // This is just empty statement. It says "do nothing"

// Your code after delay
}

If you use windows os, you can #include <Windows.h> and then use function Sleep(number_of_milliseconds), but I don't recommend this, because your code will not work on other operating systems.

Answer 2

#include <cstdlib>
#include <iostream>
int main()
{
std::cout << "Sleeping for 2 seconds ..." << std::endl;
system("sleep 2");
return 0;
}

As simple.But it has some performance issues
http://www.cplusplus.com/articles/j3wTURfi/

Unix has a variety of sleep APIs (sleep, usleep, nanosleep). The only Win32 function I know of for sleep is Sleep(), which is in units of milliseconds.

//For unix
#include <unistd.h>
#include <iostream>

int main()
{
std::cout << "Sleeping for 2 seconds ..." << std::endl;
sleep(2);
return 0;
}

//For Windows

#include <windows.h>
#include <iostream>

int main()
{
std::cout << "Sleeping for 2 seconds ..." << std::endl;
Sleep(2);//Note the S(uppercase)
return 0;
}