1、设计一个周期 3 的多表代替密码并予以实现，要求：第 1 个表由密钥字法

产生（密钥字自拟），第 2 个表由洗牌法产生（注意，字母 a~z 与数字 0~25

一一对应，洗牌法即相当于实验一的方法1（n=25）），第三个表由公式法

产生（数学公式自拟，注意它须是 Z26上的一个一一变换）。

2、设计一个周期 5 的 16-置换移位密码并予以实现，要求：5 个 16-置换至少有一个是由实验一（n=15）提供的两个方法以外、自行设计的其它方法产生。

-With the C programming language, the list is stored in a single structure, on a number of classes (in two classes for example) student achievement management, requirements to achieve the following functions:

(1) through a terminal or file a number of students enter the class number, student number, results, data from each class were stored in a different single chain, the data element stored by order of highest to lowest scores　and then were sequentially (high to low) output each class of transcr ipt.

(2) input classes, number and performance changes (such as+5,-3), at least 1 person on the results of each class were modified and still maintain the data in descending order by score　and then were sequentially output of each class of transcr ipt.

(3) the total number of each class are output, the highest score, lowest score, average