Quick Answer: What Is Null And Void Pointer?

What we Cannot do on a void pointer?

Explanation: Because the void pointer is used to cast the variables only, So pointer arithmetic can’t be done in a void pointer..

What is generic pointer and its need?

A void pointer is a special pointer that can point to object of any type. A void pointer is typeless pointer also known as generic pointer. void pointer is an approach towards generic functions and generic programming in C. Note: Writing programs without being constrained by data type is known as generic programming.

Is null a keyword in C?

Traditionally, the NULL macro is an implementation defined constant representing a null pointer, usually the integer 0 . … In C, the NULL macro can have type void * . However, in C++ this definition is invalid, as there is no implicit cast from a void * type to any other pointer type (which C allows).

What is difference between null and void?

The difference between null and void as term for nothing stems from their place in physical space. A void is nothing but takes up space; null is nothing at all. In other words, you could measure a void but null offers nothing to measure.

What is generic pointer?

It make sense to have a pointer type that can hold the address of any data type. When a variable is declared as being a pointer to type void it is known as a generic pointer.

What happens if you free a NULL pointer?

The free() function shall cause the space pointed to by ptr to be deallocated; that is, made available for further allocation. If ptr is a null pointer, no action shall occur.

What is a void pointer?

The void pointer in C is a pointer which is not associated with any data types. It points to some data location in the storage means points to the address of variables. It is also called general purpose pointer. In C, malloc() and calloc() functions return void * or generic pointers.

WHAT IS NULL pointer with example?

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.

What does void * mean?

Using a void * means that the function can take a pointer that doesn’t need to be a specific type. For example, in socket functions, you have send(void * pData, int nLength) this means you can call it in many ways, for example char * data = “blah”; send(data, strlen(data)); POINT p; p.

Can we assign null to void pointer?

Infact you can assign NULL /0 to pointer of any type. So NULL is nullpointer constant.

What is size of void pointer?

The size of void pointer varies system to system. If the system is 16-bit, size of void pointer is 2 bytes. If the system is 32-bit, size of void pointer is 4 bytes. If the system is 64-bit, size of void pointer is 8 bytes.

How do I print a void pointer?

The pointer value itself is rarely interesting, but you can print it with printf(“%p\n”, out); . The %p formatting specifier is for void * . printf(“%p\n”, out); is the correct way to print a (void*) pointer.

How do I check if a pointer is valid?

To check if a pointer is valid when using pointers concept first initialize all pointers to zero. Then if you cannot find any pointer initialization then check that it is non-0 before deleting it. When we delete a pointer first we have to make the pointer point to null then delete it.

What is size of generic pointer?

4 bytesWhat is size of generic pointer in C++ (in 32-bit platform)? Explanation: Size of any type of pointer is 4 bytes in 32-bit platforms.

Can we typecast void into int?

void pointer in C / C++ A void pointer can hold address of any type and can be typcasted to any type. Note that the above program compiles in C, but doesn’t compile in C++. In C++, we must explicitly typecast return value of malloc to (int *).