题目5：利用条件运算符的嵌套来完成此题：学习成绩>=90分的同学用A表示，60 -89分之间的用B表示，60分以下的用C表示。 -Title 5: use condition operator nesting to complete this problem: academic record > = 90 points with A classmate said, 60 Between 89- points with B said, 60 point

个人通信录c++版完整代码，记录了同学（包含一起上学的学校名称）、同事（包含共事的单位名称）、朋友（包含认识的地点）、亲戚（包含称呼）等与本人有关人员的数据集。-Personal communications recorded c++ version of the full code, record the students (including name of the school to school together), colleagues (including working with