编译原理----词法分析程序----C语言版

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
char KeyWord[20][100]={
"begin",
"end",
"if",
"while",
"var",
"procedure",
"else",
"for",
"do",
"int",
"read",
"write"
};
char yunsuanfu[]="+-*/<>%=";
char fenjiefu[]=",;(){}:";
int main()
{
char test[]="var a=10;\nvar b,c;\nprocedure p; \n\tbegin\n\t\tc=a+b\n\tend\n";
int len_yunsuanfu=strlen(yunsuanfu);
int len_fenjiefu=strlen(fenjiefu);
puts(test);
int length=strlen(test),i,j,k;
for(i=0;i<length;i++)
{
if(test[i]==' '||test[i]=='\n'||test[i]=='\t')
continue;
int tag=0;
for(j=0;j<len_fenjiefu;j++)
{
if(fenjiefu [j]==test[i]){
printf("分界符\t%c\n",test[i]);
tag=1;
break;
}
}
if(tag==1)
continue;
tag=0;
for(j=0;j<len_yunsuanfu;j++)
{
if(yunsuanfu[j]==test[i]){
printf("运算符\t%c\n",test[i]);
tag=1;
break;
}
}
if(tag==1)
continue;
if(test[i]>='0'&&test[i]<='9')
{
printf("数字\t");
while(test[i]>='0'&&test[i]<='9')
{
printf("%c",test[i]);
i++;
}
printf("\n");
continue;
}
char temp[100];
j=0;
while(test[i]>='0'&&test[i]<='9'||test[i]>='a'&&test[i]<='z'||test[i]>='A'&&test[i]<='Z'||test[i]=='_')
{
temp[j++]=test[i];
i++;
}
i--;
temp[j++]='\0';
tag=0;
for(j=0;j<20;j++){
if(strcmp(temp,KeyWord[j])==0)
{
tag=1;
printf("关键字\t%s\n",temp);
break;
}
}
if(tag==0)
printf("标识符\t%s\n",temp);
}
}