typedef struct node
{
    struct goods data;
    struct node *next;
}Node,*Link;
后面为什么有两个标识符呢？

Node abc 相当于 struct node abc
Link pabc 相当于 struct node *pabc  

typedef struct node
{
    struct goods data;
    struct node *next;
}Node,*Link;

此处相当于
struct node
{
    struct goods data;
    struct node *next
};
用typedef 给结构体期了别名
typedef struct node Node;
typedef struct node *Link;