Reading input from stdin until empty line

I want to parse input such as:

1 2 3\n4 5 6\n7 8 9\n\n

and for each row save each value in int ant print it to stdout until I get an empty line, so for this example I would get:

I've tried something like

int n1, n2, n3;
while(scanf ("%d %d %d\n", n1, n2, n3) != EOF) {
    printf("%d %d %d\n", n1, n2, n3);
    fflush(stdout);
}

but it doesn't seem to work. Is there any simple way to do that?

Solution

scanf cannot achieve what you are trying to do because it keeps reading until the condition is met, and %d specifier will ignore '\n' newline character, I propose this code

#include <stdio.h>
#include <string.h>

int  main()
{
    int n1, n2, n3;
    char line[64];

    /* read at least 63 characters or unitl newline charater is encountered with */
    /*    fgets(line, sizeof line, stdin) */
    /* if the first character is a newline, then it's an empty line of input */
    while ((fgets(line, sizeof line, stdin) != NULL) && (line[0] != '\n'))
    {
        /* parse the read line with sscanf */
        if (sscanf(line, "%d%d%d", &n1, &n2, &n3) == 3)
        {
            printf("%d %d %d\n", n1, n2, n3);
            fflush(stdout);
        }
    }
    return 0;
}

While this code works it's not robust, since it will fail in the case commented below by WhozCraig, so this is a way to do it that will keep you safe from the problem

#include <stdio.h>
#include <string.h>
#include <ctype.h> /* for isspace */

int isEmpty(const char *line)
{
    /* check if the string consists only of spaces. */
    while (*line != '\0')
    {
        if (isspace(*line) == 0)
            return 0;
        line++;
    }
    return 1;
}

int  main()
{
    int n1, n2, n3;
    char line[64];

    while ((fgets(line, sizeof line, stdin) != NULL) && (isEmpty(line) == 0))
    {
        if (sscanf(line, "%d%d%d", &n1, &n2, &n3) == 3)
        {
            printf("%d %d %d\n", n1, n2, n3);
            fflush(stdout);
        }
    }
    return 0;
}