定义一个处理学生的类Student，该类包含学号、成绩和姓名等成员数据（学号不能相同）以及若干成员函数。另外定义一个全局函数max()，返回n个学生中成绩最高者。-Define a handle students'　class Student, the class includes learning, accomplishment and name the member data (Student ID is not the same) as well as several member functions. Another definition of a global function max (), returns the n highest achievements of students.