[C++] sleep() and usleep() Not Working for Me

[dodle]

I've been trying to figure out how to get my program to pause for a second or two. I've found sleep() and usleep(), but neither are working as they have been explained to do.

These are a couple of locations I got my information from:
http://ubuntuforums.org/showthread.php?t=1425188&highlight=sleep
http://www.dreamincode.net/forums/topic/16391-sleep-command-in-c/

The program should first print out "Hello ", wait 2 seconds then print out "World". But "Hello World" is printed out all at once after a 2 second pause:

Using sleep()

#include <iostream>
using namespace std;

int main()
{
cout << "Hello ";
sleep(2);
cout << "World";
cout << endl;

return 0;
}


Using usleep()

#include <iostream>
using namespace std;

int main()
{
cout << "Hello ";
usleep(2000000);
cout << "World";
cout << endl;

return 0;
}

Am I not using the functions correctly?

[Compyx]

Since the standard library uses buffered I/O, you need to flush the output buffer (holding "Hello") before sleeping. In C I would use

fflush(stdout);, in C++ I believe
cout.flush(); should do the trick. A newline will also flush the output buffer, but that would break up "Hello World" over two lines.

[dodle]

Thanks Compyx(Commodore), that does just as you say.