C Programming - Typedef - Discussion

What is char P?

Please tell me whether p is a character constant or simply a constant.

const p;

The syntax itself having the keyword "const" which indicates the constant values.

P is a constant pointer.

'const charp p' doesn't translate to 'const char* p'

Think of it this way:

const int x;//means x is an integer constant.
const charp p;//means p is a charp constant.

The purpose of typedef is to form complex types from more-basic machine types and assign simpler names to such combinations.[wikipedia]

It doesn't just carry out string substitution like #define Macros.

C program to buttress my point.

#include<stdio.h>
int main()
{
typedef char *charp;
const charp p="ABCD";
p="XYZ";
printf("%s",p);
return 0;
/*output is a compiler error stating that p is read-only.
so assigning "XYZ" is illegal*/
}

However,

#define charp char*
#include<stdio.h>
int main()
{
const charp p="ABCD";
p="XYZ";
printf("%s",p);
return 0;
/* executes fine. output is XYZ*/
}

P is a constant because it defines.

And it's a type of pointer type.

typedef char *charp=> charp is character pointer
but
const charp P => P it is simply constant

P is a pointer to constant of type char.

P is the pointer to char constant

Option A is Right,

1. typedef char *charptr;

So charptr contain one address and *charptr contain any constant;

2. const charptr p;

If p='a' and &p=0x10;
Now charptr contain &p(0x10)

Only for address we are keeping const, not for value in that address. So P that is constant.

p can't be pointer, since with typedef we can't modify the actual base type,we just only give new name to existing type. That's all folks.