编译原理C语言词法分析器

/*运算符表*/
int xx0[35],xx1[10],xx2[31];
int temp_key3=0,temp_c40=0,temp_c41=0,temp_c42=0,temp_c43=0;
/*******初始化函数*******/
void load()
{
int mm;
for (mm=0;mm<=34;mm++)
return;
}
fclose (floading);
/*建立保留字表文件:key0、txt*/
if ((floading=fopen("key1、txt","w"))==NULL)
{
printf("Error! Can't create file : key1、txt");
return;
}
/*建立分隔符表文件:key1、txt*/
/*建立浮点类型常量表文件:c41、txt*/
if ((floading=fopen("c42、txt","w"))==NULL)
{
printf("Error! Can't create file : c42、txt");
{
printf("Error! Can't create file : key3、txt");
return;
}
fclose (floading);
/*建立标识符表文件:key3、txt*/
if ((floading=fopen("c40、txt","w"))==NULL)
{
printf("Error! Can't create file : c40、txt");
{
xx0[mm]=0;
}
for (mm=0;mm<=9;mm++)
{
xx1[mm]=0;
}
for (mm=0;mm<=30;mm++)
{
xx2[mm]=0;
}
FILE *floading;
if ((floading=fopen("key0、txt","w"))==NULL)
{
printf("Error! Can't create file : key0、txt");
#include <string、h>
#include <stdlib、h>
char *key0[]={" ","auto","break","case","char","const","continue","default","do","double","else","enum","extern","float","for","goto","if","int","long","register","return","short","signed","sizeof","static","struct","switch","typedef","_Complex","_Imaginary","union","unsigned","void","volatile","while"};
if ((floading=fopen("key2、txt","w"))==NULL)
{
printf("Error! Can't create file : key2、txt");
return;
}
fclose(floading);
/*建立运算符表文件:key2、txt*/
if ((floading=fopen("key3、txt","w"))==NULL)
void inta_search(char *word)void cc_search(char *word)
四、设计
1、主函数void main ( )
2、初始化函数void load ( )
3、保留字及标识符判断函数void char_search(char *word)
4、整数类型判断函数void inta_search(char *word)
/*保留字表*/
char *key1[]={" ","(",")","[","]","{","}",",",";","'"};
/*分隔符表*/
char *key2[]={" ","+","-","*","/","%","<",">","==",">=","<=","!=","!","&&","||","<<",">>","~","|","^","&","=","?:","->","++","--","、","+=","-=","*=","/="};
二、实验目的
1、理解词法分析在编译程序中的作用;
2、掌握词法分析程序的实现方法与技术;
3、加深对有穷自动机模型的理解。
三、主要函数
void load ( )void char_search(char *word)
void main ( )void intb_searchan ( )void c_search(char *word)
编译原理 C语言词法分析器
一、实验题目
编制并调试C词法分析程序。
a.txt源代码:
main() {
int sum=0 ,it=1;/* Variable declaration*/
if (sum==1)
it++;
else
it=it+2;
}
设计其词法分析程序,能识别出所有的关键字、标识符、常数、运算符(包括复合运算符,如++)、界符;能过滤掉源程序中的注释、空格、制表符、换行符;并且能够对一些词法规则的错误进行必要的处理,如:标识符只能由字母、数字与下划线组成,且第一个字符必须为字母或下划线。实验要求:要给出所分析语言的词法说明,相应的状态转换图,单词的种别编码方案,词法分析程序的主要算法思想等。
return;
}
fclose (floading);
/*建立整数类型常量表文件:c40、txt*/
if ((floading=fopen("c41、txt","w"))==NULL)
{
printf("Error! Can't create file : c41、txt");
return;
}
fclose (floading);
5、浮点类型判断函数void intb_search(char *word)
6、字符串常量判断函数void cc_search(char *word)
7、字符常量判断函数void c_search(char *word)
同4、5函数图
8、主扫描函数void scan ( )
五、关键代码
#include <stdio、h>