Why is a pointer with a value of 0 Not a valid address?

It’s not even an address abstraction, it’s the constant specified by the C standard and the compiler can translate it to some other number as long as it makes sure it never equals a “real” address, and equals other null pointers if 0 is not the best value to use for the platform.

Why would a pointer be null?

A null pointer is a pointer which points nothing. Some uses of the null pointer are: a) To initialize a pointer variable when that pointer variable isn’t assigned any valid memory address yet. So that, we can perform error handling in pointer related code e.g. dereference pointer variable only if it’s not NULL.

Is 0 considered null in C?

‘\0’ is defined to be a null character. It is a character with all bits set to zero. This has nothing to do with pointers. ‘\0’ is (like all character literals) an integer constant with the value zero.

Is a null pointer 0?

The null pointer constant is always 0. The NULL macro may be defined by the implementation as a naked 0 , or a cast expression like (void *) 0 , or some other zero-valued integer expression (hence the “implementation defined” language in the standard). The null pointer value may be something other than 0.

IS NULL pointer 0x0?

You just must not assume that a null pointer has 0 as a pointer value or points to 0x0 as that is nowhere defined. That is the case for all current implementations widely in use but it would not violate the standard if it wasn’t.

Is 0x0 same as null?

0x0 is just equivalent to 0 in hexadecimal notation. NULL is a macro which is defined as 0 too. while rootItem->parent() will return 0x0 ( that is literal 0 and literal 0 always means null *)as there is no parent of rootItem and it points to nothing, that’s exactly what a “nullptr” is.

What is the address of a null pointer?

What is a NULL pointer? NULL is a predefined Macro, and its value is 0 (since 0 is not a valid memory address, thus we can consider that NULL can be used for nothing or no address). So, NULL pointer is a pointer variable that is assigned with NULL Macro.

How do you differentiate between zero and NULL?

“Zero” is a value. It is the unique, known quantity of zero, which is meaningful in arithmetic and other math. “Null” is a non-value. It is a “placeholder” for a data value that is not known or not specified.