Question

Suppose a dynamic variable was created as follows:

char *x;

x = new char;
(a) Let's say that the value of the pointer variable x has not changed ( so it still points to the same dynamic variable), how can you destroy this new dynamic variable and return the memory it uses to the free store manager so that the memory can be reused to create other new dynamic variables?

(b) In your own words, describe the action of the new operator. What does the new operator return? What are the indications of errors

Answer 1

To deallocate the memory assigned to a dynamic variable in C++, the 'delete' operator is used. The 'new' operator allocates memory for an object and returns a pointer, throwing 'bad_alloc' on failure or a null pointer when using the 'nothrow' variant.

Step-by-step explanation:

To destroy a dynamically allocated variable and return its memory to the free store manager, you can use the delete operator. Here is how you would do it for the variable x that was created:

delete x;

This line of code deallocates the memory that x points to and returns it to the pool of available memory, allowing for the creation of other dynamic variables.

About the new Operator

The new operator in C++ is used for dynamic memory allocation. It allocates memory for a single object or an array of objects of a given type and returns a pointer to the first byte of the allocated space. The new operator does two things: it allocates memory and then calls the constructor (for non-primitive data types). If the allocation is successful, it returns a pointer to the allocated memory. However, if it fails to allocate memory, in C++ prior to C++11, it throws a bad_alloc exception or, in the case of using the nothrow version of new, returns a null pointer.