1. calloc(...) allocates a block of memory for
an array of elements of a certain size. By default the block is
initialized to 0. The total number of memory allocated will be (number_of_elements
malloc(...) takes in only a single argument which is the memory
required in bytes. malloc(...) allocated bytes of memory and not
blocks of memory like calloc(...).
2. malloc(...) allocates memory blocks and returns a void pointer to
the allocated space, or NULL if there is insufficient memory
calloc(...) allocates an array in memory with elements initialized
to 0 and returns a pointer to the allocated space. calloc(...) calls
malloc(...) in order to use the C++ _set_new_mode function to set
the new handler mode.