Question

I am try to read in some data with an id followed by firstname lastname from a text file and I cannot seem to get scanf to allow the space.

input may look like:
123456 FirstName LastName

scanf("%d%s", &id, fullName) doesn’t work because it cuts off at the space between first and last name. I would like to have ‘first last’ in one string (preferrably without concat because there are instances where the last name is not included).

Answer 1

You can use the set notation to specify a set of allowable characters in your name, and explicitly allow spaces:

scanf("%d %[ a-zA-Z]", &id, fullName);

Here, [] specifies a set of characters to allow (see man 3 scanf), and within there there is a space, a-z, which means “all lower-case characters” and A-Z which means “all upper-case characters.

All that said, you should specify a maximum width, to avoid overflowing your buffer. For example:

char fullName[64]; // allocate 64-byte array and set to 0
scanf("%d %63[ a-zA-Z]", &id, fullName);

Note the use of 63 instead of 64; the man page notes that it will read in the number of characters specified, and then a NULL-terminator:

String input conversions store a null terminator (‘\0’) to mark the end of the input; the maximum field width does not include this terminator.