When is static memory allocation

You cannot change the size of the array once the memory is allocated. In the above code snippet, the declaration of the array is static in nature, and memory is allocated at compile time itself. This is an example of static memory allocation because the size of the array is fixed, i. You cannot alter the size of the array at the runtime of the program. Deletion of static memory is totally dependent on the scope of a variable.

As soon as the scope of the variable is over, allocated memory gets freed. The disadvantages of static memory allocation Most of the time static memory allocation results in wastage of the memory, which cannot be freed when it is no longer needed.

It uses stack data structures. Disadvantages: Memory wastage problem. Exact memory requirements must be known. Dynamic Memory Allocation. In Dynamic memory allocation size initialization and allocation are done by the programmer. It is managed and served with pointers that point to the newly allocated memory space in an area which we call the heap. Heap memory is unorganized and it is treated as a resource when you require the use of it if not release it. When everything is done during run time or execution time it is known as Dynamic memory allocation.

Key Features: Dynamic allocated at runtime We can also reallocate memory size if needed. Dynamic Allocation is done at run time. No memory wastage There are some functions available in the stdlib.

There is a need to specify the number of bytes of memory that are required to be allocated as the argument returns the address of the first byte of memory that is allocated because you get an address returned, a pointer is the only place to put it. It allocates memory as a number of elements of a given size. It initializes the memory that is allocated so that all bytes are zero. Size of each data item. It is very similar to using malloc but the big plus is that you know the memory area will be initialized to zero.

Stack memory is allocated during compilation time execution. This is known as static memory allocation. Whereas, heap memory is allocated at run-time compilation. This is know as dynamic memory allocation. In Static Memory Allocation the memory for your data is allocated when the program starts. The size is fixed when the program is created. The memory allocation is done either before or at the time of program execution.

The address can be found using the address of operator and can be assigned to a pointer. The memory is allocated during compile time. Take a step-up from those "Hello World" programs. Learn to implement data structures like Heap, Stacks, Linked List and many more! Check out our Data Structures in C course to start learning today.