#include <stdio.h>
#include <string.h>
#include <conio.h>
#include <ctype.h>
char prog[80]={'\0'},token[8];
char ch;
int syn,n,sum,m,p;
char *rwtab[6]={"begin","if","then","while","do","end"};
void scaner()
{
m=0;
sum=0;
for(n=0;n<8;n++)
token[n]='\0';
ch=prog[p++];
while(ch==' ')
ch=prog[p++];
if(isalpha(ch))
{
while(isalpha(ch)||isdigit(ch))
{
token[m++]=ch;
ch=prog[p++];
}
token[m++]='\0';
ch=prog[p--];
syn=10;
for(n=0;n<6;n++)
if(strcmp(token,rwtab[n])==0)
{
syn=n+1;
break;
}
}
else
if(isdigit(ch))
{
while(isdigit(ch))
{
sum=sum*10+ch-'0';
ch=prog[p++];
}
ch=prog[p--];
syn=11;
}
else
switch(ch)
{
case'<':m=0;token[m++]=ch;ch=prog[p++];
if(ch=='>')
{
syn=21;
token[m++]=ch;
}
else if(ch=='=')
{
syn=22;
token[m++]=ch;
}
else
{
syn=20;
ch=prog[p--];
}
break;
case'>':m=0;token[m++]=ch;ch=prog[p++];
if(ch=='=')
{
syn=24;
token[m++]=ch;
}
else
{
syn=23;
ch=prog[p--];
}
break;
case':':m=0;token[m++]=ch;ch=prog[p++];
if(ch=='=')
{
syn=18;
token[m++]=ch;
}
else
{
syn=17;
ch=prog[p--];
}
break;
case'+':syn=13;token[0]=ch;break;
case'-':syn=14;token[0]=ch;break;
case'*':syn=15;token[0]=ch;break;
case'/':syn=16;token[0]=ch;break;
case'=':syn=25;token[0]=ch;break;
case';':syn=26;token[0]=ch;break;
case'(':syn=27;token[0]=ch;break;
case')':syn=28;token[0]=ch;break;
case'#':syn=0;token[0]=ch;break;
default:syn=-1;
}
}
main()
{
p=0;
printf("\n请输入需要分析的字符串,以#表示结束:");
do
{
ch=getchar();
prog[p++]=ch;
}while(ch!='#');
p=0;
do
{
scaner();
switch(syn)
{
case 11: printf("(%d,%d)\n",syn,sum);break;
case -1: printf("\n 出错;\n");break;
default: printf("(%d,%s)\n",syn,token);
}
}while(syn!=0);
getch();
}