cifafenxi.txt

词法分析程序 共初学者阅览与参考 如有问题可联系我 进一步作探讨!

#include<STDIO.H>    
#include<STRING.H>    
#include<CTYPE.H>    
#include<IOSTREAM.H>    
#define SIZE 128    
#define NONE -1    
#define FILENAME  "c:\\cifa.txt"    
   
char ch;   
int r;   
int i;   
int j;   
int lineno=1;   
char token[SIZE];   
get_char();   
void cleartoken();   
char lexbuf[SIZE];   
void concat();   
void printf_id(char s[50],int a);   
   
void main ()   
{   
    int f=0;   
    int e;   
    printf("lexical analysis begin now---\n");   
    printf("IF YOU WANT INPUT FROM THE KEYBOARD,PLEASE PUT 0!\n");   
    printf("IF YOU WANT INPUT FROM THE TEXT,PLEASE PUT 1!\n");   
    scanf("%d",&e);   
    if(e==1)   
    {   
    FILE *fp;   
  //  char str[10];    
 //  puts("Please iuput a file name()");    
  // gets(str);    
 //  scanf("%s/n",&str);    
//  while(fopen(NAME,"r")==NULL)    
 //  {    
 //  puts("Error!");    
 //  gets(str);    
 //  }    
if((fp=fopen(FILENAME,"r"))==NULL)   
    {   
    printf("cannot open this file\n");   
    }   
else    printf("File Begin:\n\n");   
   fp=fopen(FILENAME,"r");   
   while(feof(fp)==0)   
   {   
    lexbuf[f]=fgetc(fp);   
    ++f;   
   }                   
    }   
//if((fp=fopen(FILENAME,"r"))==NULL)    
//  {    
//  printf("cannot open this file\n");    
//  }    
 //   printf("File Begin:\n\n")    
   
    else if(e==0)   
    {   
        puts("riweir\n");   
        printf("please input your words.\n");   
        printf("uu\n");   
  //    gets(lexbuf);    
    cin.get(lexbuf,SIZE);   
    //canf("%s",lexbuf);    
        printf("uu\n");   
        f=strlen(lexbuf);   
        printf("%d\n",f);      
    }   
        r=0;   
do{     
    ch=get_char();   
    if(ch==' '||ch=='\t')   
        {   
           ;   
        }   
    else if(ch=='\n')   
        {    
            cleartoken();   
            lineno++;   
        }   
    else if(isdigit(ch))   
        {     
           concat();   
           ch=get_char();   
           printf("digit ertey :\n");   
           while(isdigit(ch))   
           {   
           concat();   
           ch=get_char();   
           }   
   
        printf("digit 12:%s\n",token);   
           
            --r;   
          cleartoken();   
    }      
    else if(isalpha(ch))   
        {   
         concat();   
         ch=get_char();   
        while(isalnum(ch))   
        {   
        concat();   
        ch=get_char();   
        }     
      if(strcmp(token,"begin")==0)   
        printf_id(token,1);   
      else if(strcmp("end",token)==0)   
        printf_id(token,2);       
      else if(strcmp("if",token)==0)   
        printf_id(token,3);       
      else if(strcmp("then",token)==0)   
        printf_id(token,4);         
      else if(strcmp("for",token)==0)   
        printf_id(token,5);          
      else if(strcmp("do",token)==0)   
        printf_id(token,6);           
      else if(strcmp("while",token)==0)   
        printf_id(token,7);           
      else if(strcmp("var",token)==0)   
        printf_id(token,8);           
      else if(strcmp("integer",token)==0)   
        printf_id(token,9);    
      else if(strcmp("real",token)==0)   
        printf_id(token,10);   
      else printf("iden 11:%s\n",token);   
            --r;   
            cleartoken();   
    }   
    else if(ch=='(')   
        {   
            printf("symb 23: (\n");   
            cleartoken();   
        }   
    else if(ch=='/')   
        {   
       ch=get_char();   
       if(ch=='*')   
             {   
                ch=get_char();   
                while(ch!='*'||lexbuf[r]!='/')   
                  {    
                     ch=get_char();   
                  }   
                ch=get_char();   
               cleartoken();   
             }   
           
       else if(ch=='/')   
            {   
                ch=get_char();   
                while(ch!='\n')   
                ch=get_char();   
                
                cleartoken();   
       }   
     else {    
            printf("symb 23: /\n");   
            --r;   
         }   
        }   
    else if(ch=='>')   
        {   
              ch=get_char();   
             if(ch=='=')   
                 printf("symb 19:>=\n");   
             else { printf("symb 18:>\n");   
                    --r;    
             }   
          cleartoken();   
        }   
     else if(ch=='<')   
        {   
            ch=get_char();   
            if(ch=='=')   
                printf("symb 21:<=\n");   
            else   
               { printf("symb 20:<\n");   
                --r;   
            }   
                cleartoken();   
        }   
    else if(ch==':')   
     {   
        ch=get_char();   
        if(ch=='=')   
         printf("symb 13: :=\n");   
        else {  printf("symb 13: :\n");   
            --r;}   
     }      
    else if(ch=='+')   
     {   
         printf("symb 14: +\n");   
     }   
    else if(ch=='-')   
     {   
         printf("symb 15:-\n");   
     }   
    else if(ch=='*')   
     {   
         printf("symb 16:*\n");   
     }   
   
    else if(ch=='=')   
     {   
         printf("symb 22: =\n");   
     }   
   
    else if(ch==';')   
     {   
         printf("symb 23: ;\n");   
     }   
    else if(ch==',')   
     {   
         printf("symb 24: ,\n");   
     }   
   
    else if(ch==')')   
     {   
         printf("symb 26: )\n");   
     }   
    }while(r<=f);   
}   
get_char()   
{      
    char w;   
    w=lexbuf[r];   
    r++;   
    return (w);   
}   
void printf_id(char s[50],int n)   
{   
    printf("word %d:%s\n",n,s);   
}   
void cleartoken()   
{   
    int len;   
    for(len=0;len<SIZE;LEN++) pre < } token[len]="\0" len="strlen(token);" len; int { concat() void ;>  
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