标准c语言词法分析(c语言描述)

实验内容：

实现标准C语言词法分析器

实验目的：

1．掌握程序设计语言词法分析的设计方法；

2．掌握DFA的设计与使用方法；

3．掌握正规式到有限自动机的构造方法；

实验要求：

1．单词种别编码要求

基本字（关键字）、运算符、界符：一符一种；

标识符（变量名）：统一为一种；

常量（）：按类型编码；

2．词法分析工作过程中建立符号表、常量表，并以文本文件形式输出；

3．词法分析的最后结果以文本文件形式输出；

4．完成对所设计词法分析器的功能测试，并给出测试数据和实验结果；

5．为增加程序可读性，请在程序中进行适当注释说明；

6．整理上机步骤，总结经验和体会；

7．认真完成并按时提交实验报告。

# include<stdio.h>

# include <string.h>

# include <stdlib.h>

# include <time.h>

# include <ctype.h>

FILE *fr,*fw,*temp1,*temp2;

char

*key0[]={"main","printf","scanf","else","if","auto","double","int","struct","break","long","switch","case","enum","register","typedef","char","extern","return","union","const","float","short","unsigned","continue","for","signed","void","default","goto","sizeof","volatile","do","while","static"};

/*关键字表*/

char *key1[]={"\"","\\","%%","(",")","[","]","{","}",",",";","'"};

/*边界符表*/

char *key2[]={"

","+","-","*","/","%","<",">","==",">=","<=","!=","!","&&","||","<<",">>","~","|","^","&","=","?:","->","++","--",".","+=","-=","*=","/="};

/*运算符表*/

int isLet(char c)//判断是否是字母