array of typedef struct declared inside class

[Ryuuji]

Hi everyone!


I'm encountering problem about typedef struct. The case was i declared a struct inside a class like this:

class Myclass
{
private:

typedef struct MysampleStruct{
int x;
int y;
}Mysample[3];
}

If I'm going to use this struct like this:

Mysample[0].x = 1;

I'm having an error like "expected unqualified-id '[' token".

But if I'm gonna delete the 'typedef' in 'typedef struct MysampleStruct', its working fine.

Can someone explain to me why these happen?

Thanks in advance.

[Cubbi]

Just drop the keyword 'typedef'. It's completely unnecessary when it comes to declaring structs, and, in this case, is just wrong.

[Ryuuji]

Hi Sir Cubbi. I'm new using this implementation, what does typedef do here? why am i having that kind of error? Thanks in advance

[Cubbi]

typedef here generates an error.

In general, typedef creates a type alias:

struct A {...}; // creates the type "A"
A s1; // creates an object of type A;
typedef A B; // creates the type "B" as an alias of "A"
B s2; // creates an object of type B (or A, they are the same) 

You're allowed to create a type and its alias simultaneously:

typedef struct A {...} B; // creates two aliased types "A" and "B"
A s1;
B s2; // same as A s2; 

You're allowed to create a type and construct an array of objects of that type simultaneously:

struct A {...} array[3]; // creates the type A and constructs an array of three As

But you can't create a type, create a type alias, and construct an array of objects of that type all on the same line.