c - How to read numbers from file and calculate the mean?

I have a list of numbers in my *.txt file:

1 2  
3

called numbers.txt. I need to read them and calculate the mean, for my file it will be: (1 + 2 + 3) / 3 = 2; Although my code shows some wrong results, it read 3 two times. Why is that, how to solve it?

My code:

#include 
#include 

double fun(const char *filename)

{
    double sum = 0, mean = 0, tmp = 0;
    int i = 0;
    FILE *f;
    if((f = fopen(filename, "r")) == NULL)
    {
        exit(-1);
    }

    while(!feof(f))

    {
        fscanf(f, "%lf", &tmp);
        printf("tmp = %f \n", tmp);
        sum += tmp;
        ++ i;
    }

    i = i - 1;
    mean = sum / i;


    fclose(f);

    printf("i = %d\n", i);
    printf("sum = %f\n", sum);
    printf("mean = %f\n", mean);

    return mean;
}

int main(int argc, char **argv)

{
    fun("numbers.txt");

    return 0;
}