how to sleep in c [duplicate]

问题

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Closed 7 years ago.

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)?

回答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);
}

来源：https://stackoverflow.com/questions/13385850/how-to-sleep-in-c