Why should we typedef a struct so often in C?

Question

I have seen many programs consisting of structures like the one below

typedef struct 
{
    int i;
    char k;
} elem;

elem user;

Why is i

Answer 1

I don't think forward declarations are even possible with typedef. Use of struct, enum, and union allow for forwarding declarations when dependencies (knows about) is bidirectional.

Style: Use of typedef in C++ makes quite a bit of sense. It can almost be necessary when dealing with templates that require multiple and/or variable parameters. The typedef helps keep the naming straight.

Not so in the C programming language. The use of typedef most often serves no purpose but to obfuscate the data structure usage. Since only { struct (6), enum (4), union (5) } number of keystrokes are used to declare a data type there is almost no use for the aliasing of the struct. Is that data type a union or a struct? Using the straightforward non-typdefed declaration lets you know right away what type it is.

Notice how Linux is written with strict avoidance of this aliasing nonsense typedef brings. The result is a minimalist and clean style.

Answer 2

Turns out in C99 typedef is required. It is outdated, but a lot of tools (ala HackRank) use c99 as its pure C implementation. And typedef is required there.

I'm not saying they should change (maybe have two C options) if the requirement changed, those of us studing for interviews on the site would be SOL.

Answer 3

Using a typedef avoids having to write struct every time you declare a variable of that type:

struct elem
{
 int i;
 char k;
};
elem user; // compile error!
struct elem user; // this is correct