What does the struct declaration typedef struct A { … } B; mean?

Question

What is the name of the struct below — node_t or node? Why is there any difference?

typedef struct node_t
{
    int data;
    struct node_t *right, *left;
}   node;

possible duplicate of [typedef struct vs struct definitions](http://stackoverflow.com/questions/1675351/typedef-struct-vs-struct-definitions) — Jonathan Leffler, Jun 30 '14 at 15:21
It means putting an alias `node` to `struct node_t`. (`node_t` is struct tag name in C) — BLUEPIXY, Jun 30 '14 at 23:15

Helio Santos · Answer 1 · 2014-06-30T16:18:00.357

4

You are defining a name (node) for the struct node_t.

It allows you to create the structure using node myStruct instead of struct node_t myStruct.

edited Jun 30 '14 at 16:18

answered Jun 30 '14 at 14:04

Helio Santos

So just for complete understanding - node is related to the typedef? and allows me to call the struct without using the word struct? and the name of the struct is node_t? – noyuzi Jun 30 '14 at 14:06
it's the same as making a new type for an int - typedef int myint; but for a struct. – AnthonyLambert Jun 30 '14 at 14:18
Yes, yes, and no. The name of the struct (struct node_t) is node; – Jiminion Jun 30 '14 at 14:18
@noyuzi `typedef foo bar` declares the type `bar` as a synonym to `foo`, so `foo my_var` is equivalent to `bar my_var`. In this case, `foo`=`struct node_t` and `bar`=`node`. – humodz Jun 30 '14 at 14:56
Note that C++ has different rules and would not require the `typedef`; you could write `struct node { int data; node *right; node *left; };` and then use `node` as the name of a type (indeed, you've already used `node` as the name of the type inside the structure). – Jonathan Leffler Jun 30 '14 at 15:20

1 Answers1