Can we delete NULL pointer?

Deleting a null pointer has no effect. It's not good coding style necessarily because it's not needed, but it's not bad either. If you are searching for good coding practices consider using smart pointers instead so then you don't need to delete at all. It is safe unless you overloaded the delete operator.

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Keeping this in view, can we delete NULL pointer in C++?

Explanation: Deleting a null pointer has no effect, so it is not necessary to check for a null pointer before calling delete.

Additionally, can we delete this pointer? Answer: Yes, we can delete “this” pointer inside a member function only if the function call is made by the class object that has been created dynamically i.e. using “new” keyword. As, delete can only be applied on the object that has been created by using “new” keyword only.

In respect to this, does delete make pointer null?

In assignment operators, a delete is typically followed by an assignment anyway. If you have an array of pointers, and your second action is to delete the empty array, then there is no point setting each value to null when the memory is about to be freed. If you want it to be null..

What happens when you delete a pointer?

3 Answers. The pointer itself does have an address and the value. The address of the pointer does not change after you perform delete on it. The standard does not say what happens to the value of the pointer; all it says is that you are no longer allowed to use that value until you assign your pointer a valid value.

Related Question Answers

How does delete [] work?

Delete is an operator that is used to destroy array and non-array(pointer) objects which are created by new expression.

1. Delete can be used by either using Delete operator or Delete [ ] operator.
2. New operator is used for dynamic memory allocation which puts variables on heap memory.

What is Unique_ptr?

std::unique_ptr is a smart pointer that owns and manages another object through a pointer and disposes of that object when the unique_ptr goes out of scope. The object is disposed of using the associated deleter when either of the following happens: the managing unique_ptr object is destroyed.

What is this pointer in C++?

C++ this Pointer. Every object in C++ has access to its own address through an important pointer called this pointer. The this pointer is an implicit parameter to all member functions. Therefore, inside a member function, this may be used to refer to the invoking object.

What is smart pointer in C++?

Smart pointers are objects which store pointers to dynamically allocated (heap) objects. They behave much like built-in C++ pointers except that they automatically delete the object pointed to at the appropriate time. They can also be used to keep track of dynamically allocated objects shared by multiple owners.

What is malloc in C++?

C++ malloc() The malloc() function in C++ allocates a block of uninitialized memory and returns a void pointer to the first byte of the allocated memory block if the allocation succeeds. It may or may not be a null pointer.

What is Raii in C++?

Resource Acquisition Is Initialization or RAII, is a C++ programming technique which binds the life cycle of a resource that must be acquired before use (allocated heap memory, thread of execution, open socket, open file, locked mutex, disk space, database connection—anything that exists in limited supply) to the

Does delete call destructor?

Yes, the destructor will be called for all objects in the array when using delete[] . If a constructed object can be in such a state that calling the destructor would be invalid, then there's something seriously wrong with your object. You need to make your destructor work in all cases.

Can I use delete with malloc?

It is perfectly legal, moral, and wholesome to use malloc() and delete in the same program, or to use new and free() in the same program. But it is illegal, immoral, and despicable to call free() with a pointer allocated via new, or to call delete on a pointer allocated via malloc().

What will happen if you malloc and free instead of delete?

7 Answers. When you call delete a pointer, the compiler will call the dtor of the class for you automatically, but free won't. (Also new will call ctor of the class, malloc won't.) In you example, a char array apparently don't have a dtor, so delete does nothing but return the memory.

How does free works in C?

Using free() Function in C The function free() is used to de-allocate the memory allocated by the functions malloc ( ), calloc ( ), etc, and return it to heap so that it can be used for other purposes. The argument of the function free ( ) is the pointer to the memory which is to be freed.

What is free store in C++?

C++ Free Store. « Previous Tutorial Next Tutorial » Free Store is a pool of unallocated heap memory given to a program that is used by the program for dynamic allocation during the execution of program. Every program is provided with a pool of unallocated heap memory that it may utilize during the execution.

What is memory management in C++?

new and delete operators in C++ for dynamic memory. Dynamic memory allocation in C/C++ refers to performing memory allocation manually by programmer. Dynamically allocated memory is allocated on Heap and non-static and local variables get memory allocated on Stack (Refer Memory Layout C Programs for details).

How do you delete a pointer in C++?

In C++, delete operator should only be used either for the pointers pointing to the memory allocated using new operator or for a NULL pointer, and free() should only be used either for the pointers pointing to the memory allocated using malloc() or for a NULL pointer.

Can Make_unique return Nullptr?

C++ std::unique_ptr return from function and test for null If the function succeeds, it shall return a pointer to a object with data. If it fails, it should return null .

Is delete this safe?

It's safe to delete "this" as long as it's essentially the last operation in the method. In fact several professional level APIs do so (see ATL's CComObject implementation for an example). The only danger is attempting to access any other member data after calling "delete this". This is certainly unsafe.

Is it fine to call delete twice for a pointer?

It is undefined behavior to call delete twice on a pointer. Anything can happen, the program may crash or produce nothing.

Can you delete a const pointer C++?

E2158: Operand of 'delete' must be non-const pointer (C++) It is illegal to delete a variable that is not a pointer. It is also illegal to delete a pointer to a constant.

How do you delete an object in C++?

When delete is used to deallocate memory for a C++ class object, the object's destructor is called before the object's memory is deallocated (if the object has a destructor). If the operand to the delete operator is a modifiable l-value, its value is undefined after the object is deleted.

How do I delete in C++?

For a delete , if the pointer passed is a base class of the actual object's type, the base class must have a virtual destructor (otherwise, behavior is undefined). If it is not a base class, then the destructor of that class is called, and a operator delete in that class or the global operator delete is used.