一、 实验目的
（1）认识DOS；
（2）掌握命令解释程序的原理；
（3）掌握简单的DOS调用方法；
（4）掌握C语言编程初步。
二、 实验内容和要求
编写类似于DOS，UNIX的命令行解释程序
（1）自行定义系统提示符
（2）自定义命令集（8-10个）
（3）用户输入HELP以查找命令的帮助
（4）列出命令的功能，区分内部还是外部命令
（5）用户输入QUIT退出
（6）内部命令有dir, cd, md,rd, cls, date, time, ren, copy等。
根据要求，完成设计、编码、测试工作。
三、 实验方法、步骤及结果测试
3.主要程序段及其解释：
#include<stdio.h> #include<string.h> void main() /*主函数*/ { char *b[11]={"dir","cd","md","rd","cls","date","time","ren","copy","help", "quit"}; /*指针数组存储关键字*/ int pan(char ch1[],char *j[11]); char a[10],*p=a; printf("欢迎来到dos系统 "); printf("quit ：退出 help：显示所有功能 "); c1: printf("请输入命令："); scanf("%s",a); pan(p,b); /*函数调用*/ if(strcmp(a,b[10])!=0) /*比较输入的字符串是否quit结束命令*/ goto c1; else printf("out of work!! "); } int pan(char ch1[],char *j[11]) /*子函数*/ { int i; for( i=0;i<11;i++) if(strcmp(ch1,j[i])==0) /*比较输入的字符串与数组的关键字是否相等*/ { switch(i) { case 0:printf("command name is dir. It's function is list file. It's an internal command. Volume in drive K gas no label. Volume Serial Number is 60F0-6C24 ");break; case 1:printf("command name is cd. It's function is change directory. It's an internal command. ");break; case 2:printf("command name is md. It's function is creat a new directory. It's an internal command. ");break; case 3:printf("command name is rd. It's function is delete a directory which is empty. It's an internal command. ");break; case 4:printf("command name is cls. It's function is clean screen It's an internal command. ");break; case 5:printf("command name is date. It's function is show date. It's an internal command. ");break; case 6:printf("command name is time. It's function is shio time. It's an internal command. ");break; case 7:printf("command name is ren. It's function is rename a file. It's an internal command. ");break; case 8:printf("command name is copy. It's function is copy files. It's an internal command. ");break; case 9:printf("dir cd md rd cls date time ren copy Enter " quit" to quit this program!! ");break; case 10:printf("Thanks for using it,bye!! ");break; } return 1;} printf("No this one!! Not a internal commal. ");return 0; }
四、运行结果截图及分析
当打开运行界面时，就出现
欢迎来到dos系统
quit ：退出 help：显示所有功能
请输入命令：
然后当你输入各种命令就会出现相应的字符串
输入help就会出现所有命令
输入quit就会退出界面。
四、实验心得
通过这个简单地编写dos系统的程序，让我更加清楚更更加了解操作系统这门课，虽然程序很简单，功能也很简单，不过对我们来说挺有意义的。最开始学习操作系统这门课的时候，说实在的，对操作系统这个概念很模糊，觉得很抽象。然后后来慢慢学习之后发现挺有趣的，还可以自己编写简单的dos系统，给了我一些信心。