Thread: Difference between typdefing and declaring structs

What's the difference between this:

Code:

struct aStruct {
       int aNumber;
};

and

Code:

typedef struct {
      int aNumber;
} aStruct;

All I can think of is maybe the compiler will replace aStruct with the actual struct{} definition with typedef?

I think that the typedef is common in C so you dont have to type struct each time you declared an object (or use one) of that structure. But essentially they are the same thing.

so you dont have to do:

Code:

struct Foo {
   int a, b;
};

int main () {
   struct Foo testData;
}

Instead you can do...

Code:

typedef struct {
   int a, b;
} Foo;

int main () {
   Foo testData;
}

It's usefull in C because you must specify a struct with "struct" even when declaring or passing the struct, so the client doesn't need to know that Foo is a structure.

So really it has no difference in C++, just C?

I see