词法分析器

分析器有个问题一直无法解决,分析完会出现27和28。

#include<stdio.h>
#include<stdlib.h>
void main()
{
int i;
char s[100];
printf("请输入字符串:");
scanf("%s",&s);
for(i=0;i<100;i++)
{
if(s[i]=='b'&&s[i+1]=='e'&&s[i+2]=='g'&&s[i+3]=='i'&&s[i+4]=='n')
printf("1 , begin ");
else if(s[i]=='i'&&s[i+1]=='f')
printf("2 , if ");
else if(s[i]=='t'&&s[i+1]=='h'&&s[i+2]=='e'&&s[i+3]=='n')
printf("3 , then ");
else if(s[i]=='w'&&s[i+1]=='h'&&s[i+2]=='i'&&s[i+3]=='l'&&s[i+4]=='e')
printf("4 , while ");
else if(s[i]=='d'&&s[i+1]=='o')
printf("5 , do ");
else if(s[i]=='e'&&s[i+1]=='n'&&s[i+2]=='d')
printf("6 , end ");
else if(s[i]=='l'&&s[i+1]=='('&&s[i+2]=='l'&&s[i+3]=='|'&&s[i+3]=='d'&&s[i+3]==')'&&s[i+4]=='*')
printf("10 , l(l|d)* ");
else if(s[i]=='d'&&s[i+1]=='d'&&s[i+2]=='*')
printf("11 , dd* ");
else if(s[i]=='-')
printf("14 , - ");
else if(s[i]=='*')
printf("15 , * ");
else if(s[i]=='/')
printf("16 , / ");
else if(s[i]==':'&&s[i+1]!='=')
printf("17 , : ");
else if(s[i]==':'&&s[i+1]=='=')
printf("18 , := ");
else if(s[i]=='<'&&s[i+1]!='='&&s[i+1]!='>')
printf("20 , < ");
else if(s[i]=='<'&&s[i+1]=='=')
printf("21 , <= ");
else if(s[i]=='<'&&s[i+1]=='>')
printf("22 , <> ");
else if(s[i]=='>'&&s[i+1]!='=')
printf("23 , > ");
else if(s[i]=='>'&&s[i+1]=='=')
printf("24 , >= ");
else if(s[i]=='=')
printf("25 , = ");
else if(s[i]==';')
printf("26 , ; ");
else if(s[i]=='(')
printf("27 , ( ");
else if(s[i]==')')
printf("28 , ) ");
else if(s[i]=='#')
printf("0 , # ");

}

}

原文地址:https://www.cnblogs.com/BOXczx/p/5937909.html