期末作业要求如下：

Write a program that will help elementary school pupils practice math. a) The program will first ask the user for his/her ID number (including two letters & 4 digits), e.g. Please input your four digit ID no: AB1234 The program should have input validation. Then the program prompts three choices: (1) Start a test (2) Check scores (3) Exit Test: the program will give 10 math problems, e.g.: 12 * 3 = 36 48 + 32 = 80 … 56 / 28 = 2 Note: i) Pupils will answer each problem before the next one is given. ii) The problems should include addition, subtraction, multiplication and division. They are randomly generated. iii) Randomly generates numbers for problems. However, must ensure that both the problem and the result are no larger than two digits. The problem and the result should be greater than or equal to zero. The divisor cannot be zero. iv) After ten problems are finished, record the time used by the student to do the ten problems. v) Gives a score to each student. Saves this student’s ID, his/her score and the time used into a file named ‘record.txt’. vi) Print the following information on the screen: Prob. | Correct Answ. | Ur Answ c) Check scores: Searches the file ‘record.txt’ and lists all the historical scores for this student, e.g.: Your previous records are: AB1234 80 150 seconds AB1234 50 182 seconds AB1234 90 98 seconds You will be marked based on your program’s: (1) Correctiveness (2) Readability (3) Robustness (4) Conciseness

目前本人的程序可以直接使用，并完全满足要求。还是建议学弟学妹在字里行间多多理解，争取自己写出漂亮的代码！

向本人在完成此作业过程中参考的代码表示衷心的感谢！