getting text to print character by character in C

Question

int main() {
    int i;
    char words[] = "Hello this is text.\n";
    for(i = 0; i < strlen(words); i++) {
        sleep(1);
        putchar(words[i]);
    }
}

I've been attempting to have the program output the text slowly, character by character into the console (to look like someone is typing it). However instead when I run this code I get one massive pause, and then it prints the whole string at once. How do I get this to work.

(also no C++ solutions please)

can u use function usleep, here you can pass arguments in miliseconds instead of seconds. Also look at http://stackoverflow.com/questions/14818084/what-is-the-proper-include-for-the-function-sleep-in-c — lordkain, Jul 27 '16 at 06:22
use [`fflush`](http://linux.die.net/man/3/fflush) after putchar — dvhh, Jul 27 '16 at 06:22

kfsone · Answer 1 · 2016-07-27T06:43:11.233

4

stdio is buffered to make it more efficient, writing a single character isn't enough to get it to write it's buffer to the console. You need to flush stdout:

#include <stdio.h>

int main() {
    int i;
    char words[] = "Hello this is text.\n";
    for(i = 0; i < strlen(words); i++) {
        sleep(1);
        putchar(words[i]);
        fflush(stdout);
    }
}

edited Jul 27 '16 at 06:43

answered Jul 27 '16 at 06:22

kfsone

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You forgot to `#include ` and `#include ` in your answer. – user3078414 Jul 27 '16 at 08:11

score 3 · Answer 2 · answered Jul 27 '16 at 06:22

3

That's because the standard output is line buffered by default.

Flush the output after each character like this:

putchar(words[i]);
fflush(stdout);  //<---

answered Jul 27 '16 at 06:22

Yu Hao

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getting text to print character by character in C

2 Answers2