要求统计并输出一个表格，表格内容包括学号，各课分数，总分和平均分，并标出三门均在90分以上者 实现对两个字符串大小的比较 编程打印出n*n（n＜0）阶的方阵-demand and output a statistical tables, forms, including the contents of the course scores, the total score and average hours and three were marked in 90 hours or more to