c - Why is {typedef int* PTR;const PTR p=#} not equivalent to "const int* p=&num" but to "int *const p=&num"? -

this thing partly touched upon in question on so, casually not main question. confusion still persists, putting in separate question.

why following 2 statements equivalent int* const p=&num , not const int* p=&num when latter seems more logical , intuitive? rigorous reasons behavior of typedef?

typedef int* ptr; const ptr p=# 

and finally, in question 1 member remarks bad practice use typedefed pointers. have seen being used in many books , websites , seems convenient thing do. makes code more understandable. final word on it? should 1 avoid typedefed pointers as possible?

edit: , correct syntax typedef statement if intend following:

  const int* const p=# 

edit: inadvertently forgot ask important thing. correct syntax using typedef statement following then?

  const int* p=#      //instead of int* const p=&num got 

generally,

const type var = ini; 

declares const variable var of type type. so

const ptr p=# 

declares const variable p of type ptr, initialised address of num.

a typedef not textual alias, can't replace typedefed name expansion see results in.

if want get

const int* const p=# 

with typedef, must typedef including const int, e.g.

typedef const int *ci_ptr; 

and can write

const ci_ptr p = # 

(but don't, it's ugly).

and for

const int *p = # 

you can write

ci_ptr p = # 

and finally,in question 1 member remarks bad practice use typedefed pointers.but have seen being used in many books , websites , seems convenient thing do,that makes code more understandable.

whether makes code more understandable or less depends. 1 thing in experience bad thing typedef pointer types names hide fact dealing pointers.

typedef struct list_node {     int value;     struct list_node next; } *node; 

for example 1 unfortunately common abuse. when read type node, don't suspect it's pointer. @ least typedef node_ptr. then, why typedef pointer @ all, typedefing structure , using node* shorter , clearer.

so final word on it? should 1 avoid typedefed pointers as possible?

there's no ultimate authority on it, it's decision. follow coding style in company/project if there one, use judgment if you're coding on own.