关于学生选课系统的c语言编程。假定有n门课程，每门课程有课程编号、课程名称、课程性质、总学时、授课学时、实验或商机学时、血粉、开课学期等信息，学生可按要求（如总学分不得少于60）自由选课。-C programming language student elective system. Assume that there are n courses, each course course number, course name, course nature, total hours, teaching hours, the hours of the experiment or business opportunities, blood meal, semester, students upon request (such as not less than 60 total credits) free elective.