定义一个学生类，包括四门课的成绩。学生对象随机输入，观看vector容器剩余的空间，直到

发生重新分配为止。使用sort或stable_sort对它进行排序，可用学号或总成绩或任一门课程为关键字

（重载operator<或函数对象类Comp）。-Definition of a student class, including four course results. Students object random input, see the remaining space vector container, until the occurrence of re-allocated. Use the sort or stable_sort sort it, can learn numbers, or a total score or any of the course for the keyword (overloading operator < or function object class Comp).