Why declare struct's with keyword 'typedef'?

Hello,

In other people's source code, I have often seen structures declared in both of the following manners:

struct sample {
...
};

typedef struct sample {
...
};

I do not understand why the keyword 'typedef' is used at times. When I remove the keyword, the programs appear to run in the same manner as when I have the keyword there. If someone could clarify why 'typedef' is placed before structure definitions, that would be helpful. Thanks.

Fierytycoon

Actually, your second definition is incorrect: it should be

typedef struct
{
...
} name;

This is a hangover from the C days when you had to put struct in front of name if it was a structure. To make life easier, they type defined the struct to be name. In C++, because struct is just class public, there is no need to typedef struct.

Quote:

---

Originally posted by Fierytycoon
Hello,

In other people's source code, I have often seen structures declared in both of the following manners:

struct sample {
...
};

typedef struct sample {
...
};

I do not understand why the keyword 'typedef' is used at times. When I remove the keyword, the programs appear to run in the same manner as when I have the keyword there. If someone could clarify why 'typedef' is placed before structure definitions, that would be helpful. Thanks.

Fierytycoon

---

To add to Cup's answer, if these definitions are in a header file, and you intend to use the header in both 'C' and C++ source files, you should leave the "typedef struct" alone. The obvious reason is that the 'C' compiler will throw a fit if you declare your structure the "C++" way :)

Regards,

Paul McKenzie

ah, I see. Thanks to both of you for all of your input.

Fierytycoon