c - What is the advantage of specifying two types when creating a typedef'd struct? -

example 1:

struct t{     int a; }; 

creates type struct t

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example 2:

typedef struct {     int a; } t; 

creates type t

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example 3:

typedef struct t{     int a; } t; 

creates both types struct t , t

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i tend see example 3 lot, , i'm not sure why choose on example 1 or 2.

• are there advantages gain doing way?
• are there reasons people compatibility?
• is advantageous kind of scoping reason?

i avoid doing example 3 way, because less maintenance on type, , restricts multiple ways of declaring same thing. however, reconsider it, if there benefits "double naming" technique.

i tend see example 3 lot, , i'm not sure why choose on example 1 or 2.

• are there advantages gain doing way?

i hold truth self-evident, namely cumbersome code cumbersome. prefer write

t object; 

instead of

struct t object; 

however, hard-core c coder might think hey, t struct, better call that , also, mitigates chance confusion you'd when doing

struct {int a; } t; typedef int t;  

• are there reasons people compatibility?

yes. way, structs in c can used used in c++.

• is advantageous kind of scoping reason?

no, not i'd aware of.