Question

I am going through some examples in a book I have and I have come to something I’ve never seen before nor understand:

scanf("%d-%d-%d-%d-%d", &prefix, &group, &publisher, &item, &check_digit);

This code is part of a program that asks the user to enter their ISBN number of a book and later on breaks down the ISBN into Prefix = x, Group = y, etc..

I have NEVER seen the hypens between the %d‘s. Does anyone see any point in this??

Thanks

Answer 1

“Pattern matching”. If the input doesn’t fit the specified pattern (also called format), it fails. So if you input anything else than INT-INT-INT-INT-INT (where INT is a placeholder for an integer you input), the input would be considered invalid.