How does the scanf function work in C?

Question

Why do you require ampersand (&) in the scanf function. What will the output or type of error (compile or runtime) be in the following C code?

Answer 1

If you're asking a question like this, I would recommend just learning for now "it just does".

You will learn that you need an ampersand because scanf takes one or more pointer arguments. If a is an int variable, it is not a pointer. &a ("the address of a") is a pointer, so it will work with scanf.