Merge two linked lists in ascending order

Two linked lists have been created, and both are written in ascending order of student numbers. A function is required to merge the two linked lists in ascending order. # Include <stdlib. h>
# Include <stdio. h>
# Include <conio. h>
# Include <ctype. h>

# Define Len sizeof (struct student)

Extern unsigned _ floatconvert;/* prevents floating point formats not linked errors */
# Pragma extref _ floatconvert

Typedef struct student
{
Long num;
Float score;
Struct student * next;
} Stu;

Stu * createend ()
{
Int n = 0;
Stu * P1, * P2, * head;
Head = NULL;
P1 = (Stu *) malloc (LEN);/* create the first node */
Scanf ("% lD, % F", & P1-> num, & P1-> score );
P1-> next = NULL;
While (P1-> num! = 0)/* add nodes to the linked list */
{
++ N;
If (n = 1)/* is the first node as the header */
Head = p1;
Else/* not the first node, end as the table */
P2-> next = p1;
P2 = p1;
P1 = (Stu *) malloc (LEN);/* open the next node */
Scanf ("% lD, % F", & P1-> num, & P1-> score );
P1-> next = NULL;
}
Free (P1);/* release the memory occupied by the last node */
Return (head);/* return the head pointer of the linked list */
}

Void print (Stu * head)
{
Stu * P;
P = head;
Do
{
Printf ("% LD \ t % 5.1f \ n", p-> num, p-> score );
P = p-> next;
} While (P! = NULL );
}

Stu * Merge (Stu * P1, Stu * P2)
{
Stu * P, * head;
If (P1-> num <P2-> num)
{
Head = P = p1; P1 = p1-> next ;}
Else
{
Head = P = P2; P2 = P2-> next ;}
While (P1! = NULL & p2! = NULL)
If (P1-> num <P2-> num)
{
P-> next = p1;
P = p1;
P1 = p1-> next;
}
Else
{
P-> next = P2;
P = P2;
P2 = P2-> next;
}
If (P1! = NULL)
P-> next = p1;
Else
P-> next = P2;
Return head;
}

Void main ()
{
Stu * P1, * P2, * head;
Printf ("Please input first link information: \ n ");
P1 = createend ();
Print (P1 );
Printf ("\ nplease input second link information: \ n ");
P2 = createend ();
Print (P2 );
Printf ("\ nthe merged link is: \ n ");
Head = Merge (P1, P2 );
Print (head );
Getch ();
}