malloc - allocates memory.
calloc - allocates memory of n blocks of size. initializes values to zero.
realloc - reallocates (expands/shrinks) memory allocation.
free - releases allocation
void *malloc ( unsigned int size )
Usage: pnt = (type *)malloc(size)
void *calloc ( unsigned int number, unsigned int size )
Usage: pnt = (type *)calloc(number, size)
void *realloc ( void *old_pnt, unsigned int new_size )
Usage: new_pnt = (type *)realloc(old_pnt, new_size)
void free ( void *pnt )
Usage: free(pnt)