未命名1.cpp

简单的词法分析器 利用vc编程 功能 可以打开任意位置和名称的原文件进行词法分析

/*  Experment 3_4 Define and Fullfill token file */
#include "stdio.h"
#include "string.h"
Src[80][80];
/* Static Array for source file  */
struct entry
   {
    /*define a struct */
    char word[9];
    int token;
    };
static struct entry word[60]={
"and",1,"array",2,"begin",3,"bool",4,"call",5,"case",6,
  "char",7,"constant",8,"do",9,"else",10,"end",11,"false",12,
 "for",13,"if",14,"input",15,"integer",16,"not",17,"of",18,
 "or",19,"output",20,"procedure",21,"program",22,"read",23,"real",24,
 "repeat",25,"set",26,"then",27,"to",28,"true",29,"until",30,
 "var",31,"while",32,"write",33,"标识符",34,"整常数",35,"实常数",36,
 "字符常数",37,"'",38,"(",39,")",40,"*",41,"*/",42,
 "+",43,",",44,"-",45,"`",46,"..",47,"/",48,"/*",49,":",50,":=",51,
 ";",52,"<",53,"<=",54,"<>",55,"=",56,">",57,">=",58,"[",59,"]",60
 };
int IsAlpha(char ch)      ;
int IsNum(char ch)        ;
int RecogId(char *str)    ;
int RecogInt(char *str)   ;
int RecogInt(char *str)   ;
int RecogChar(char *str)  ;
int RecogFloat(char *str) ;
int DelCom(char *str)     ;
struct entry lookup(struct entry *words,char *str) ;
int InSrc()  ;
int IsTm(char *ch);
void main()
    {   int i=0,j=0;
        char *ch="*";
        /*InSrc();Read source file into static array*/
        /*
        for(t=0;t<80;t++)
        printf("%s",Src[t]);
        */
        printf("%d",IsTm(ch));
        getch();
    }
int IsAlpha(char ch)
    {
    if((ch>='a'&&ch<='z')||(ch>='A'&&ch<='Z')||(ch>='0'&&ch<='9'))
        return 1;
    else
        return 0;
    }
int IsNum(char ch)
    {
    if(ch>='0'&&ch<='9')
        return 1;
    else
        return 0;
    }
int RecogInt(char *str)
    {
    /*Recog an leagle Int*/
    int i=0,state=0;
    while(i<=(strlen(str)-1))
        {
        if(IsNum(str[i]))
            {
            state=1;
            i++;
            }
        else
            {
            state=0;
            break;
            }
        }
    return state;
}
int RecogId(char *str)
    {
    /*Recog an ligeal Identify */
    int i=0,state=0;
    if(IsAlpha(str[0])&&!IsNum(str[0]))
    state=1;
    i=1;
    while(i<=(strlen(str)-1)&&(state==1))
        {
        if(IsAlpha(str[i])||IsNum(str[i]))
            {
            state=1;
            i++;
            }
        else
            {
            state=0;
            break;
            }
        }
    return state;
    }

int RecogChar(char *str)
    {
    /*Recog an leagle char*/
    int i=0,state=0,len=strlen(str);
    if(str[0]=='\''&&str[len-1]=='\'')
    state=1;
    i=1;
    while(i<=(strlen(str)-2)&&state==1)
        {
        if(IsAlpha(str[i]))
            {
            state=1;
            i++;
            }
        else
            {
            state=0;
            break;
            }

        }
    return state;
    }

int RecogFloat(char *str)
    {
    /*Recog an leagle Float*/
    int i,state=0,countdian=0,countE=0;
    if(IsNum(str[0]))
        state=1;
        i=1;
    while(i<=(strlen(str)-1)&&state==1)
        {
        if(IsNum(str[i])||str[i]=='.'||str[i]=='E')
            {
            state=1;
            if(str[i]=='.')
            countdian++;
            if(countdian>1)
            break;
            if(str[i]=='E')
            countE++;
            if(countE>1)
            break;
            i++;
            }
        else
            {
            state=0;
            break;
            }
        }
    return state;
 }

int DelCom(char *str)
{
/*Del comment int Src file */
int len=strlen(str);
if((str[0]=='/')&&(str[1]=='*')&&(str[len-2]=='*')&&(str[len-1]=='/'))
    return 1;
else
    return 0;

}

struct entry Lookup(char *str)
    {
    /*lookup if the input str is in table words */
    int i=0,flag=0;
    while(i<60&&flag==0)
    {
    if(strcmp(word[i].word,str)==0)
       flag=1;
    else
        i++ ;
     }
     if(flag)
     return word[i];
     else if(RecogId(str))
        return word[33];
       else if(RecogInt(str))
            return word[34];
        else if(RecogFloat(str))
            return word[35] ;
             else if(RecogChar(str))
                return word[36];
    }

int InSrc()
    {
      int i=0;
      char s[80],file1[20],file2[20];
      FILE *fp1,*fp2;                /*定义2个文件指针*/
      printf("please tpye into src file1 'name:\n");
      scanf("%s",file1);
      printf("%s\n",file1);
      printf("please tpye into des file2 'name:\n");
      scanf("%s",file2);
      printf("%s\n",file2);
      if((fp1=fopen(file1, "rb"))!=NULL)
            printf("file1 open ok !\n");/*打开当前目录名为1.txt的文件只读*/
      else
            {
            printf("file1 open erro !\n");
            exit(1);
            }
     if((fp2=fopen(file2, "wb"))!=NULL)
            printf("file2 open ok !\n");  /*打开当前目录名为2.txt的文件追加*/
     else
            {
            printf("file2 open erro !\n");
            exit(1);
            }
        printf("+++++++++++++++++++++++++++    Programe Begin   ++++++++++++++++++++++++++++++++\n");
     while(!feof(fp1))
          {
          fgets(s,80,fp1);             /*从文件中读取80个字符*/
          printf("%s",s);              /*输出所读的字符串*/
          strcpy(Src[i],s);/*将当前文件中读出的一行拷贝到原程序数组中*/
          i++;/*下次拷下一行*/
          fputs(s,fp2);
          }
        printf("\n\n+++++++++++++++++++++++++      Programe End     ++++++++++++++++++++++++++++++++\n");
    if(!fclose(fp1))                   /*关闭文件1*/
               printf("Close file1 ok\n");
    else
              printf("Close file1 Erro\n");
    if(!fclose(fp2))                   /*关闭文件2*/
               printf("Close file2 ok\n");
    else
              printf("Close file2 Erro\n");
              getch();
              return 0;
}
int IsTm(char *ch)
    {
    /*判断字符是否为终结符*/
    struct entry temp;
    temp=Lookup(ch);
   if(temp.token>=38&&temp.token<=60)
        return temp.token;
   else
        return 0;

    }