How to print only certain parts of a string?

Question

I have a string const char[15] and I want to print it like this:

Label-one: characters [0,13)
Label-two: characters [

Answer 1

printf("Label-one: %.*s", 13, str);
printf("Label-two: %.*s", 2, str + 13);

@Bob's answer is also acceptable if these lengths are constant, but in case the lengths are determined at runtime, this is the best approach since it parametrises them.