Difference between different ways of malloc

struct node{
  int w;
  int x;
}
struct node *item;

1. Please explain the difference between these statements.


2. 
   

   i read as typecasting after malloc is not needed. why is that so?

   
   

   1) item = malloc(sizeof(*item));

   
   

   2) item = malloc(sizeof(struct node));

   
   

   3) item = (struct node *) malloc(sizeof(struct node));