링크 길이 계산

#include
#include

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:
");
    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:
");
        scanf("%d",&n);

    }
}

void printf_link(Lstudent *ptri)
{
    ptri=ptri->next;/////////////////////////////////////////////////
    while(ptri!=NULL)
    {
    printf("%d   ",ptri->num);
    ptri=ptri->next;
    }
}
unsigned int ListLength(Lstudent *ptr)
{
    unsigned int l=0;
    ptr=ptr->next;//    
    while(ptr!=NULL)
    {
        l++;
        ptr=ptr->next;
    }
    return l;
}
int main()
{
    LPstudent head;
    InitLink(&head);
    printf_link(head);
    unsigned int a=ListLength(head);
    printf("%u
",a);
}