#include <stdio.h>  #include <string.h>#define max 100  char a[max],b[8],ch;  int syn,p,m,n,sum;  char word[][6]={"begin","if","then","while","do","end"};   void mor(){        sum=0;      ch=a[p++];      m=0;          while((ch==‘ ‘)||(ch==‘\n‘)||(ch==‘\t‘))          ch=a[p++];      if(((ch<=‘z‘)&&(ch>=‘a‘))||((ch<=‘Z‘)&&(ch>=‘A‘)))      {        while(((ch<=‘z‘)&&(ch>=‘a‘))||((ch<=‘Z‘)&&(ch>=‘A‘))||((ch>=‘0‘)&&(ch<=‘9‘)))          {              b[m++]=ch;              ch=a[p++];          }            p--;         syn=10;                            for(n=0;n<6;n++)             if(strcmp(b,word[n])==0)              {               syn=n+1;                 break;             }      }                                       else if((ch>=‘0‘)&&(ch<=‘9‘))      {          while((ch>=‘0‘)&&(ch<=‘9‘))         {             sum=sum*10+ch-‘0‘;               ch=a[p++];         }         p--;         syn=11;      }      else                      {          switch(ch)          {          case ‘+‘:              syn=13;              b[m++]=ch;                      break;          case ‘-‘:               syn=14;            b[m++]=ch;               break;         case ‘*‘:              syn=15;              b[m++]=ch;              break;          case ‘/‘:              syn=16;              b[m++]=ch;              break;          case ‘:‘:              b[m++]=ch;              ch=a[p++];              if(ch==‘=‘)              {                  syn=18;                  b[m++]=ch;              }              else              {                   syn=18;                  p--;              }              break;         case ‘<‘:            b[m++]=ch;              ch=a[p++];              if(ch==‘=‘)              {                   syn=21;                  b[m++]=ch;              }              else              {                    syn=20;                  p--;              }              break;          case ‘>‘:              b[m++]=ch;              ch=a[p++];              if(ch==‘=‘)              {                  syn=24;                  b[m++]=ch;              }              else              {                   syn=23;                  p--;              }              break;        case ‘=‘:              syn=25;              b[m++]=ch;              break;          case ‘;‘:              syn=26;              b[m++]=ch;              break;          case ‘(‘:               syn=27;              b[m++]=ch;              break;          case ‘)‘:              syn=28;              b[m++]=ch;              break;          case ‘#‘:               syn=0;              b[m++]=ch;              break;         case ‘!‘:             syn=-2;            break;        default:              syn=-1;              break;          }      }      b[m++]=‘\0‘;  }main()  {    p=0;      printf("请输入一段程序段，便于词法分析(以!作为结束符):");     do{        scanf("%c",&a[p++]);        }while(a[p-1]!=‘!‘);         p=0;      do{          mor();          switch(syn)          {              case 11:                  printf("( %-5d%10d )\n",syn,sum);                  break;              case -1:                  printf("你输入一个错的字符\n");                    return 0;                  break;            case -2:                break;            default:                   printf("( %-5d%10s )\n",syn,b);                  break;          }      }while(syn!=-2);  }