how to sleep in c [duplicate]

Question

Possible Duplicate:
Why does printf not flush after the call unless a newline is in the format string?

When I run something like

for (i = 1; i <= 10; i++) {
    sleep(1);
    printf(".");
}

then what I would expect is one dot per second ten times. What I get is ten dots once after ten seconds. Why is that so, and how do I get the program to actually print one point (or do other things) each second (or different time interval)?

Answer 1

The printf() is buffering the data, you can force it to flush that data with fflush(stdout):

for (i = 1; i<=10; i++) 
{  
    sleep(1); 
    printf("."); 
    fflush(stdout);
}