这是一个字母或数制之间的转化程序，5为主模块，调用模块1和模块7

模块1又调用模块2、3、4和6四个模块，其中：

　　模块2实现小写字母向大写字母的转换

模块3实现大写字母向小写字母的转换

模块4实现二进制数向十六进制数的转换

模块6实现十六进制数向二进制数的转换

模块7实现十六进制数向十进制数的转换

按“q”键退出。

使用时，需将7个文件分别汇编，连接的方法为：

5＋1＋2＋3＋4＋6＋7

生成可执行文件“5”　即可运行。-This a letter or number into the system procedures, five main modules, Call module and a module is a 7 module called Blocks 2, 3, 4 and 6 4 module, which : Module 2 lowercase letters to the realization of capital letters conversion module to achieve three capital letters to lowercase letters conversion module is 4 is the binary number to hexadecimal number of conversion modules to achieve 6 hexadecimal number to the number of binary conversion modules into seven achieve 16 to the metric system for a few number of conversion by the "q" key to exit. Use, the need to document seven separate compilation, linking method : 5 +1 +2 +3 +4 +6 +7 generating executable files "5" will be running.