学生成绩管理系统(1)按班级按课程从文件中读入相应的平时成绩、期中考试成绩和期末考试成绩。

(2)三个成绩对总评成绩的百分比被定义为常数，各占总成绩的20 、30 和50 。

(3)计算每位学生的总评成绩。

(4)计算该班级某课程的总平均成绩。

(5)算处于优、良、中、及格、不及格的学生人数以及占总人数的百分比。其中100-90为优，89-80为良，79-70为中，69-60为及格，60分以下为不及格。

(6)按要求输出成绩在优、良、中、及格、不及格各区间的学生学号。

-Student achievement management system (1) according to the course by the class read from the file into the corresponding normal results, the results of the mid-term exam and final examination. (2) the percentage of the three scores Final Performance is defined as a constant, the total score of 20 , 30　and 50 . (3) Calculate the Final Performance of each student. (4) the overall GPA of the class of a course. (5) operator is excellent, good, fair, pass, fail the number of students as well as the total number of percentage. 100-90 gifted ,89-80 good ,79-70 ,69-60 passing, 60 points or less failed. (6) required output results in excellent, good, fair, passing, failing the interval students learn.