求大神！ 链表转置有问题 转置后只能输出两个数....

#include <iostream>

typedef struct student   //记住前面要加typedef
{
    int grade;
    student*next;
}list;

void set_list(list* &head,int a[],int n) //前插入法
{
    list *p;
    head=new list;
    head->next=NULL;
   
    for (int i=0;i<n;++i)
    {    p=new list;
        p->grade=a[i];
        p->next=head->next;
        head->next=p;
    }
   
}
void print_list(list *head)
{
    list*p=head->next;
    while(p!=NULL)
    {
        std::cout<<p->grade<<"\t";
        p=p->next;
    }
    std::cout<<std::endl;
}
bool InverseList(list*&L) //链表转置
{
    if (L->next->next==NULL)
    {return false;
    }

    list*p=L->next,*q;
    q=p->next;
    while (q!=NULL)
    {
        p->next=q->next;
        q->next=p;
        L->next=q;
        q=p->next;
    }
    return true;
}
int main()
{
    list *head;
    int a[]={1,2,5,4,4,4,7};
    set_list(head,a,7);
    print_list(head);
    InverseList(head);
    print_list(head);
}