CODEWITHSUNDEEP
c
Karthik
Karthik

Reputation: 375

Pointer initializations

char *p = "a"; is valid but not int *p = 2; and char *p = 'a'; Why are they designed like that?

Upvotes: 2

Views: 225

Answers (3)

Grijesh Chauhan
Grijesh Chauhan

Reputation: 58271

A typeof string literal is of char[n] and assignment to char* is fine.
Point is both are pointers.

char *p = "a"; means p points to string "a" (some where in memory, type of "a" is char[2]). 

   p            23   24
  +----+      +----+----+
  | 23 |      | a  | \0 |        
  +----+      +----+----+

Whereas 2 and 'a' are of int type values, not a valid address hence following declarations are errors/warnings: "initialization makes pointer from integer without a cast"

int *p = 2; and   
char *p = 'a';

note: in a char constant is int type, but not char refrence.

Upvotes: 3

hobbs
hobbs

Reputation: 239861

Because "a" has a type of char *, and 2 doesn't have a type of int *. Note that char *p = 'a' is also invalid.

Upvotes: 1

Dayal rai
Dayal rai

Reputation: 6606

Anything wrritten inside " " is considered as string in C.So

char *p = " a" says you are passing base address of string to char pointer.which is Valid.

int *p says p is a pointer to integer so p can hold a address to integer so int *p = 2 is not valid.

Similarly char *p is pointer to character so p can hold address of a character so char *p = 'a' is not valid because 'a' is just a character not address to character.

Upvotes: 4

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