编写一个函数，实现以下功能：N名学生的成绩已在主函数中放入一个带头结点的链表结构中，h指向链表的头结点。请找出学生的最高分，由函数值返回。-Write a function to achieve the following functions: N students score in the main function into a lead node in the linked list structure, and h point to the head of the list node. Please find out the highest score of the students, returned by the function value.