Dynamic Memory Allocation
C allows general purpose dynamic memory allocation on the heap, restricted only by the amount of memory available at run time
There are three predefined functions for this: (in /usr/include/stdlib.h) void * malloc(num_bytes_to_allocate); void * calloc(num_of_obj, size_of_obj); void * realloc(old_ptr, new_size_in_bytes);
If memory allocation fails, these functions return a NULL pointer.
Since these functions return a pointer to void, when allocating memory use conversion: int *pi = (int *) malloc(5*sizeof(int)); /* or: */ int *pi = (int *) calloc(5,sizeof(int)); pi = (int *) realloc(pi, 10*sizeof(int));