带头节点的后插法链表

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

typedef struct student   
{
    int num;  
    struct student *next;  
}Lstudent,*LPstudent;

void InitLink(LPstudent *phead)
{
    Lstudent *ptr,*r;
    *phead=NULL; 
    //-----------------------------------------------
    ptr=malloc(sizeof(Lstudent));
    *phead=ptr;
    ptr->next=NULL;
    //------------------------------------------------
    int n;
    printf("please input number of student:\n");
    scanf("%d",&n);
    while(n>0)
    {   
        ptr=malloc(sizeof(Lstudent));
        ptr->num=n;
        ptr->next=NULL;
        if((*phead)->next==NULL)///////////////////////////////
            (*phead)->next=ptr;//////////////////////////////////
        else
            r->next=ptr;

            r=ptr;

        printf("please input number of student:\n");
        scanf("%d",&n);

    }   
}

void printf_link(Lstudent *ptri)
{
    ptri=ptri->next;/////////////////////////////////////////////////
    while(ptri!=NULL)
    {   
    printf("%d   ",ptri->num);
    ptri=ptri->next;
    }   
}

int main()
{
    LPstudent head;
    InitLink(&head);
    printf_link(head);    

}