Question

The _______ operator is used to dynamically allocate memory.

Short answer

Answer: The missing operator is "new".

Step-by-step solution

Identifying the right operator for dynamic memory allocation

In C and C++ programming languages, the "new" operator is used for dynamic memory allocation. This operator is used to allocate memory during runtime, which can be released using the "delete" operator.

Complete the statement

Replace the blank with the identified operator. The completed statement will be: "The new operator is used to dynamically allocate memory."

Key concepts

New Operator

Dynamic memory allocation in C++ is a critical feature that enables developers to allocate memory as the program runs, a drastic shift from traditional static memory allocation that is determined during compilation. The keyword that enables this functionality is the new operator.

When a program requires memory for variables whose size cannot be predetermined, such as arrays or objects that vary depending on user input or other runtime conditions, the new operator is employed. It requests a block of memory from the heap, which is a large pool of memory used for dynamic allocation. For example, to allocate memory for an integer, one would use the following command: int *ptr = new int;. This statement allocates space for an integer and assigns its address to the pointer ptr.

It is crucial to note that unlike memory allocated on the stack, memory allocated with new remains in use until it is explicitly released. Failing to release this memory with the appropriate operator can lead to memory leaks, issues where memory is still

Runtime Memory Management

Runtime memory management involves overseeing the allocation, use, and release of memory during the execution of a program. It is an intricate part of programming, especially in languages like C++ that do not include garbage collection like some other high-level languages.

In C++, runtime memory management is largely manual and requires the programmer to be diligent in handling memory correctly to prevent leaks and fragmentation. The advantage of this level of control is that a skilled developer can optimize memory usage for performance and efficiency.

When using dynamic memory allocation, it is essential to allocate only as much memory as needed and to release it as soon as it's no longer in use. This necessitates a balance between memory efficiency and application performance. The use of tools such as profilers and static analysis can help programmers identify potential memory issues before they become critical.

Delete Operator

Paired with the new operator, C++ provides the delete operator to release the memory that was previously allocated dynamically. This memory de-allocation is as essential as allocation because it prevents memory leaks, which occur when programs do not free memory that is no longer in use.

Using the delete operator is straightforward. For a previously allocated single variable, you would release the memory using the following syntax: delete ptr;, where ptr is a pointer that was allocated with the new operator. For dynamically allocated arrays, the syntax has a slight variation: delete[] ptr;, which instructs the program to release the entire block of memory that the array consumes.

After calling delete, the pointer variable itself is not destroyed—it simply becomes a dangling pointer. Hence, it's good practice to immediately set the pointer to nullptr to avoid accidental usage of the now-invalid location.