CODEWITHSUNDEEP
cprintf
user1517073
user1517073

Reputation:

printf sleep \n

I was trying something when I saw this strange behavior. Can someone please explain it to me.

#include<stdio.h>
int main()
{
    printf("utkarsh");
    sleep(10);
    printf("dixit");
}

The expected output is print "utkarsh" then wait for 10 seconds, print "dixit" next to it. But what I observed was that it waits for 10 seconds and the prints "utkarshdixit".

If I add a \n at end of utkarsh, it works as expected. 

printf("utkarsh\n");

Could someone help me understand why am I seeing such behavior ?

Upvotes: 0

Views: 418

Answers (4)

Andy Stow Away
Andy Stow Away

Reputation: 647

There is buffering in stdout stream. Hence you need to flush once before sleep.

But when you used a '\n', the c run-time automatically flushes the stdout buffer for you. Hence you see this behaviour

Upvotes: 1

Stefano Borini
Stefano Borini

Reputation: 143795

Here, try this

#include<stdio.h>
int main()
{
    printf("utkarsh");
    fflush(stdout);
    sleep(10);
    printf("dixit");
}

There's buffering of the standard out going on. you have to explicitly flush it.

Upvotes: 2

Damien Locque
Damien Locque

Reputation: 1809

printf is buffering until you decide to write a '\n'.

You can use : flush to force to print

Upvotes: 2

DThought
DThought

Reputation: 1314

you're encoutering buffering.

try to do 

fflush(stdout);

in front of the sleep

Upvotes: 5

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