typedef int datatype: means to use the datatype string to implement the function of int. For example, after this line of definition, define an integer variable a, which can be written as datatype a, and the effect is the same as int a;

typedef struct node: As above, you can use the string "linklist" to declare a structure. The form of the structure is as above

struct node

{ datatype data;

struct node *next;

} is defined in the form. The braces are followed by a linklist, which is used to define the structure later.