scanf requiring input on multiple lines

Question

I've written this small program to work out the check digit of a barcode. Basically it's meant to take the first digit, then 2 sets of 5 digits and do some basic arithmetic on them. When inputting the first group of 5 digits, I try to enter them all on one line, like this:

>Enter the first group of 5 digits: 12345

But it's only counting the 1 and discarding the rest of the numbers. Meaning to get the program to give the correct output I have to input the data like this:

>Enter the first group of 5 digits: 1
>2
>3
>4
>5

And only then does it prompt me for the second set of 5 digits. I've tried a number of different things, such as putting spaces between the specifier in the scanf() function but it didn't work.

Does anyone have any solutions so that I will be able to enter all 5 digits on the same line of input?

Code:

#include <stdio.h>

int main(void)
{
    int d1, d2, d3, d4, d5, d6, d7, d8, d9, d10, d11, first_sum, second_sum, chk_dig;

    printf("Enter the first (single) digit: ");
    scanf("%d", &d1);

    printf("\nEnter the first group of 5 digits: ");
    scanf("%d%d%d%d%d", &d2, &d3, &d4, &d5, &d6);

    printf("\nEnter the second group of 5 digits: ");
    scanf("%d%d%d%d%d", &d7, &d8, &d9, &d10, &d11);

    first_sum = d1 + d3 + d5 + d7 + d9 + d11;
    second_sum = d2 + d4 + d6 + d8 + d10;

    chk_dig = 3 * first_sum + second_sum;

    printf("\nCheck digit: %d", 9 - ((chk_dig - 1) % 10));

    return 0;
}

Thanks!

Answer 1

If you want to scan 5 separate 1-digit numbers that are adjacent to each other, tell scanf() you want 1-digit numbers:

if (scanf("%1d%1d%1d%1d%1d", &d2, &d3, &d4, &d5, &d6) != 5)
    …some sort of format error, or EOF perhaps…

That will work OK on both the inputs:

1 2 3 4 5
12345

Answer 2

You can use spaces to separate numbers instead of new lines.

1 2 3 4 5

If you cram your numbers together, 12345, how is your program supposed to know you don't mean the actual number 12,345?

You should read the documentation on how scanf() works.