1 #include <stdio.h>   2 #include <string.h>    3 char prog[30],token[5],ch;   4 int syn,p,m,n,sum;    5 char *rwtab[6]={"begin","if","then","while","do","end"};   6 scaner();   7 main()   8 {p=0;    9  printf("请输入你要分析的程序（按“#”结束）:");  10  do{   11      scanf("%c",&ch);  12      prog[p++]=ch;  13  }while(ch!=‘#‘);  14    p=0;  15  do{  scaner();  16    switch(syn)   17    {    case 11:printf("( %-10d%5d )\n",sum,syn);  18         break;   19         case -1:printf("you have input a wrong string\n");  20         getch();  21         exit(0);   22         default: printf("( %-10s%5d )\n",token,syn);  23         break;  24 }   25 }while(syn!=0);  26   getch();   27 }  28    scaner()  29    {  sum=0;   30     for(m=0;m<8;m++)token[m++]=NULL;  31      ch=prog[p++];  32      m=0;   33  while((ch==‘ ‘)||(ch==‘\n‘))ch=prog[p++];   34  if(((ch<=‘z‘)&&(ch>=‘a‘))||((ch<=‘Z‘)&&(ch>=‘A‘)))   35  {  36      while(((ch<=‘z‘)&&(ch>=‘a‘))||((ch<=‘Z‘)&&(ch>=‘A‘))||((ch>=‘0‘)&&(ch<=‘9‘)))  37  { 38          token[m++]=ch;  39          ch=prog[p++];  40 }   41     p--;  42     syn=10; 43     for(n=0;n<6;n++)   44     if(strcmp(token,rwtab[n])==0)  45     {  syn=n+1;  46        break;   47     }  48  }   49     else if((ch>=‘0‘)&&(ch<=‘9‘))  50     {  while((ch>=‘0‘)&&(ch<=‘9‘))  51     {  sum=sum*10+ch-‘0‘;  52         ch=prog[p++];  53     }  54       p--;   55       syn=11;  56     }   57      else switch(ch)   58      {   case ‘<‘:token[m++]=ch;  59     ch=prog[p++];  60 if(ch==‘=‘)  61 {  62     syn=22;   63     token[m++]=ch;  64 }   65 else   66 {  67    syn=20;   68    p--;   69 }  70  break;   71     case ‘>‘:token[m++]=ch;  72     ch=prog[p++];  73     if(ch==‘=‘)  74     {   syn=24;   75         token[m++]=ch;  76  }  77  else   78  {    syn=23;  79        p--;  80  }  81  break;   82        case ‘+‘: token[m++]=ch;  83        ch=prog[p++];  84 if(ch==‘+‘)  85 {    syn=17;   86      token[m++]=ch;  87  }   88 else   89 {     syn=13;  90       p--;   91 }  92 break;  93         case ‘-‘:token[m++]=ch;   94            ch=prog[p++];  95     if(ch==‘-‘)  96     {        syn=29;   97          token[m++]=ch;  98     }   99         else  100         {       syn=14; 101                 p--; 102         }  103           break; 104        case ‘!‘:ch=prog[p++];105     if(ch==‘=‘) 106     { syn=21;  107       token[m++]=ch; 108     } 109     else 110     { syn=31;111        p--;112     }  113       break; 114       case ‘=‘:token[m++]=ch; 115           ch=prog[p++];116            if(ch==‘=‘) 117            { syn=25;  118               token[m++]=ch;  119            } 120       else 121       { syn=18; 122          p--; 123       } 124         break;125         case ‘*‘: syn=15;  126           token[m++]=ch;  127           break; 128         case ‘/‘: syn=16;  129            token[m++]=ch; 130            break; 131         case ‘(‘: syn=27;132             token[m++]=ch; 133             break; 134         case ‘)‘: syn=28;  135             token[m++]=ch; 136             break; 137         case ‘{‘: syn=5;  138             token[m++]=ch; 139             break; 140         case ‘}‘: syn=6;141             token[m++]=ch; 142             break; 143         case ‘;‘: syn=26;  144             token[m++]=ch; 145             break; 146         case ‘\"‘: syn=30;  147             token[m++]=ch; 148              break; 149         case ‘#‘: syn=0;  150             token[m++]=ch; 151              break; 152         case ‘:‘:syn=17;  153             token[m++]=ch;  154              break;155         default: syn=-1; 156              break; 157 }158 token[m++]=‘\0‘; 159 }