What happens if you set a pointer to NULL?

What happens if you set a pointer to NULL?

A null pointer constant can be converted to a pointer type; the result is the null pointer value of that type and is distinguishable from every other value of pointer to object or pointer to function type.” Says nothing about the address a null pointer value points to.

What is the difference between zero and NULL character?

‘\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.

Can we assign 0 to a pointer?

You can assign 0 into a pointer: ptr = 0; The null pointer is the only integer literal that may be assigned to a pointer.

What is difference between null pointer and NULL macro?

The value of NULL macro is 0. NULL is used for pointers only as it is defined as (void *) 0. It should not be used other than pointers. If NULL is assigned to a pointer, then pointer is pointing to nothing.

What do you understand by null pointer?

In computing, a null pointer or null reference is a value saved for indicating that the pointer or reference does not refer to a valid object. It might compare equal to other, valid pointers; or it might compare equal to null pointers.

Is zero a null pointer?

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).

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.

When null pointer is used?

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. b) To pass a null pointer to a function argument when we don’t want to pass any valid memory address.

Should you set a pointer to null after free?

It doesn’t hurt to set pointers to NULL after every free, but it has the potential of pointing out big problems. also to be noted that free(NULL) won’t do anything so you don’t have to write the if statement.