typedef struct vs struct definitions

I'm a beginner in C programming, but I was wondering what's the difference between using `typedef` when defining a structure versus not using `typedef`. It seems to me like there's really no difference, they accomplish the same goal.


struct myStruct{
int one;
int two;
};

vs.

typedef struct{
int one;
int two;
}myStruct;

In C (not C++), you have to declare struct variables like:

struct myStruct myVariable;

In order to be able to use `myStruct myVariable;` instead, you can `typedef` the struct:

typedef struct myStruct someStruct;
someStruct myVariable;

You can combine `struct` definition and `typedef`s it in a single statement which declares an anonymous `struct` and `typedef`s it.

typedef struct { ... } myStruct;

The difference comes in when you use the `struct`.

The first way you have to do:

struct myStruct aName;

The second way allows you to remove the keyword `struct`.

myStruct aName;

With the latter example you omit the struct keyword when using the structure. So everywhere in your code, you can write :

myStruct a;

instead of

struct myStruct a;

This save some typing, and might be more readable, but this is a matter of taste

The `typedef`, as it is with other constructs, is used to give a data type a new name. In this case it is mostly done in order to make the code cleaner:

struct myStruct blah;

vs.

myStruct blah;

Another difference not pointed out is that giving the struct a name (i.e. struct myStruct) also enables you to provide forward declarations of the struct. So in some other file, you could write:

struct myStruct;
void doit(struct myStruct *ptr);

without having to have access to the definition. What I recommend is you combine your two examples:

typedef struct myStruct{
int one;
int two;
} myStruct;

This gives you the convenience of the more concise typedef name but still allows you to use the full struct name if you need.