利用随机数产生1000个0～100之间的考试分数，将其存入一个文本文件中，然后程序从这个文件中读取这1000个考试分数，统计其中各分数段（A[90,100]，B[80,90), C[70,80), D[60,70), F[0,60)）的人数 、所占百分比，平均分。-The use of 1000 random number generator between 0 ~ 100 test scores, be deposited into a text file, and then the procedures from this document to read that 1000 test scores, statistics on the scores of paragraph (A [90100] , B [80,90), C [70,80), D [60,70), F [0,60)) the number of percentage points on average.