What are the properties of const char*? [duplicate]

char * p = ... 

is a pointer to a char. You can change the pointer, as well as the value the pointer is pointing to.

char const * p = ... const char * p = ... 

are equivalent, and are pointers to a char const. The pointer can be pointed anywhere, but it must always point to a char const.

char const * const p = ... const char * const p = ... 

are equivalent, and declare a const pointer to a char const. You can't change what the pointer is pointing to, or the value at what the pointer is pointing to.

char * const p = ... 

is a const pointer to a char. You can change the value that is pointed to, but you can't change the pointer to point somewhere else.

I am really confused what is exactly const in const char

The char is const. I.e. the pointed type is const char.

because i can change the value.

Indeed, the pointer is not const, therefore it can be made to point elsewhere by changing its value.

Is the Pointer const

No. It is a non-const pointer to const.

and what is the difference to const char

It is a non-mutable character.

or char*

It is a pointer to a character.

or char const???

Same as const char.

No, you can't change the value.

const char* ptr = "thing"; ptr[2] = 'o'; // error 

It's a pointer to const chars.

You can, however, make the pointer point to something else, because it's not a const char* const. :)

Const applies to the left, unless there's nothing there, in which case it applies to the right.