不带头结点的链表的增删改查

#include <stdio.h>
#include <stdlib.h>

#define LEN sizeof(struct student)

struct student
{
    char name[10];
    int age;
    struct student *next;
};

struct student *head = NULL;

void Create_list()
{
    struct student *p1,*p2;
    p2 = head;
    p1 = (struct student*)malloc(LEN);
    printf("Please input name and age such as (aa 1)\n");
    scanf("%s %d",p1 -> name,&p1 -> age);
    if(NULL == head)
    {
        head = p1;
        p1 -> next = NULL;
    }
    else
    {
        while(p2 -> next)
        {
            p2 = p2 -> next;
        }
        p2 -> next = p1;
        p1 -> next = NULL;
    }
}

void printlist()
{
    struct student *p = head;
    while(p)
    {
        printf("name = %s,age = %d\n",p -> name,p -> age);
        p = p -> next;
    }
}

void Add_list()
{
    struct student *p1,*p2;
    p2 = head;
    p1 = (struct student*)malloc(LEN);
    printf("Please input name and age such as (aa 1)\n");
    scanf("%s %d",p1 -> name,&p1 -> age);
    while(p2 -> next)
    {
        p2 = p2 -> next;
    }
    p2 -> next = p1;
    p1 -> next = NULL;
}

void Del_list()
{
    struct student *p1,*p2;
    char name[10];
    p2 = head;
    p1 = p2 -> next;
    printf("Please input del name:");
    scanf("%s",name);
    while(p2)
    {
        if(strcmp(p2 -> name,name) == 0 && p2 == head)
        {
            head = p1;
            p2 -> next = NULL;
            break;
        }
        else if(strcmp(p1 -> name,name) == 0)
        {
            p2 -> next = p1 -> next;
            p1 -> next = NULL;
            break;
        }
        else if(p1 -> next == NULL)
        {
            printf("can not find name to del\n");
            break;
        }
        else 
        {
            p2 = p2 -> next;
            p1 = p2 -> next;
        }
    }
}

void Update_list()
{
    struct student *p = head;
    char name[10];
    int age;
    printf("Please input name:");
    scanf("%s",name);
    printf("Please input age you want to update:");
    scanf("%d",&age);
    while(p)
    {
        if(strcmp(p -> name,name) == 0)
        {
            p -> age = age;
            break;
        }
        p = p -> next;
    }
    if(p == NULL)
    {
        printf("can not find name to update!\n");
    }
}

int main()
{
    printf("Please input num:");
    int i,n;
    printf("1.Create 2.Add 3.Del 4.Update 5.Print 6.Exit\n");
    while(1)
    {
        printf("Please input num:");
        scanf("%d",&n);
        switch(n)
        {
            case 1:Create_list();break;
            case 2:Add_list();break;
            case 3:Del_list();break;
            case 4:Update_list();break;
            case 5:printlist();break;
        }
        if(n == 6)
            break;
    }

}