Dynamic memory allocation methods give programmer management of memory when to allocate, how much to allocate and when to de-allocate. Normal native variable outlined in a perform is saved within the stack memory. The constraints of such allocations are, dimension needs to identified at compile time, we cannot change the dimensions or delete the memory. The following pictures show points with the conventional stack based allocation for an integer array. If we restrict the array dimension, then we may not be capable to store extra parts later. If we allocate extra area for array, then this causes memory wastage. Think about this drawback you probably have an array of massive objects like college students in a school. You allocate memory at runtime, giving you the ability to handle knowledge of various sizes. Dynamic resources are stored in the heap memory as a substitute of the stack. The dimensions of the array could be increased if extra parts are to be inserted and decreased of less components are inserted.here is no need to estimate the max possible measurement. The size may be determined at runtime in accordance with the requirement. The malloc() (stands for memory allocation) function is used to allocate a single block of contiguous memory on the heap at runtime. The memory allotted by malloc() is uninitialized, which means it accommodates garbage values. This operate returns a void pointer to the allocated memory that must be transformed to the pointer of required type to be usable. If allocation fails, it returns NULL pointer. Assume that we wish to create an array to store 5 integers. 20 bytes of memory. In the above malloc call, we hardcoded the variety of bytes we have to store 5 integers. However we know that the dimensions of the integer in C depends upon the structure. So, it is healthier to make use of the sizeof operator to find the scale of kind you want to store.Moreover, if there isn't any memory out there, the malloc will fail and return NULL. So, it is strongly recommended to examine for failure by comparing the ptr to NULL. The calloc() (stands for contiguous allocation) operate is much like malloc(), but it surely initializes the allotted to zero. It is used while you need memory with default zero values. This function also returns a void pointer to the allotted memory that's converted to the pointer of required type to be usable. If allocation fails, it returns NULL pointer. We are able to take the example of malloc() and try to do it with calloc() function. The memory allotted utilizing features malloc() and calloc() shouldn't be de-allocated on their own. The free() operate is used to launch dynamically allocated memory back to the working system. It is important to free memory that's no longer needed to avoid memory leaks. After freeing a memory block, the pointer turns into invalid, and it is now not pointing to a valid memory location.After calling free(), it is a good observe to set the pointer to NULL to keep away from utilizing a "dangling pointer," which points to a memory location that has been deallocated. It permits you to vary the dimensions of an existing memory allocation with out needing to free the previous memory and allocate a new block. This perform returns a pointer to the newly allocated memory, or NULL if the reallocation fails. If it fails, the original memory block remains unchanged. Suppose we initially allocate memory for five integers but later need to increase the array to carry 10 integers. It can be crucial to note that if realloc() fails and returns NULL, the unique memory block just isn't freed, so you should not overwrite the original pointer till you've successfully allotted a brand new block. Consider the first scenario where we were having points with the fixes measurement array. Let's see how we are able to each of those issues using dynamic memory allocation.