Dynamic memory allocation is a manual memory management for the dynamic memory with use of some group of functions in like malloc, realloc, calloc and free. The process of allocating memory during the execution of a C program is called a Dynamic memory allocation.
The Function that performs the same in C with their description :
malloc : allocates the specified number of bytes
realloc : increases or decreases the size of the specified block of memory. Reallocates it if needed
calloc : allocates the specified number of bytes and initializes them to zero
free : releases the specified block of memory back to the system