Question

I want to write a simple program that determines whether the number the user inputs is increasing, strictly increasing, etc. etc.

To solve this I want to break up each digit and see if they are always getting smaller or not, etc.
How do I break up the input into separate digits using scanf function?

Answer 1

One has to wonder why you’re not getting the input as integers in the first place (%llu perhaps?) – this would make comparisons so much easier. However, you could get each line from the user via fgets and then parse each character.

Since you mention you want to read large numbers:

int64_t num;
scanf("%"PRId64, &num);

Or maybe:

intmax_t num;
scanf("%jd", &num);