Programming C without variables is like, well, programming C without variables. They are so essential to the language that it doesn’t even require an analogy here. We can declare and use them… ...

This is an excellent question. Zero-length arrays, also known as flexible arrays, are used to implement variable-length arrays, primarily in structures.

Arrays are among the most common data structures. An array can store a series of data values in a linear structure, with each element accessed using its index position within the data.