malloc() and calloc()

The allocated memory supplied by calloc is zero initialised, whereas that allocated by malloc just contains whatever junk was in their before.

Also calloc takes 2 arguments one for the number of objects and one for the size of an object, whereas malloc takes just the number of bytes to be allocated. I believe memory allocated by calloc can be slightly larger than expected as the objects can be aligned to any relevant platform boundaries. The intention is for calloc to be used if items are to accessed as an array.

Hope that helps,
Charles Keepax

The function void* malloc(size_t size) is used to allocate size number of bytes.
It returns a pointer to the allocated block.

The function void* calloc(size_t nelement, size_t elementSize) allocates enough memory to store a total of nelement elements of size elementSize. You'd use this to allocate a known number of elements, such as allocating 10 my_structs:

struct my_struct
{
    int x;
    int y;
}

...

my_struct* = calloc(10, sizeof(my_struct);

It's explained in more detail here[^]

The memory is also initialized when using calloc.

Hope this helps,
Fredrik