编译原理词法分析器c++源程序

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#include<iostream.h>
#include<fstream.h>
#include<stdlib.h>
#include<stdio.h>
#include<string.h>
#include<conio.h>
#include<process.h> /*头文件*/

   void init();
      char *DchangeB(char *buf);
   int search(char *buf,int type,int command);
      void intdeal(char *buffer);
      void chardeal(char *buffer);
   void errordeal(char error,int lineno);
   void scanner();

void init()
{      char *key[]={"","auto","break","case","char","const","continue","default","do","double",
                 "else","enum","extern","float","for","goto","if","int","long","register",
                 "return","short","signed","sizeof","static","struct","switch","typedef",
                 "union","unsigned","void","volatile","while"};     /*C语言所有关键字/
    char *limit[]={" ","(",")","[","]","->",".","!","++","--","&","~",
                   "*","/","%","+","-","<<",">>","<","<=",">",">=","==","!=","&&","||",
                  "=","+=","-=","*=","/=",",",";","{","}","#","_","'"};/*运算、限界符*/
 fstream outfile;
    int i,j;
 char *c;
 outfile.open("key.txt",ios::out);
 for(i=0;i<32;i++)
  outfile<<key[i]<<endl;
 outfile.close();
 outfile.open("Limit.txt",ios::out);
 for(j=0;j<38;j++)
  outfile<<limit[j]<<endl;
 c="";
 outfile<<c;
 outfile.close();
 outfile.open("bsf.txt",ios::out);
 outfile.close();
 outfile.open("cs.txt",ios::out);
 outfile.close();
 outfile.open("output.txt",ios::out);
 outfile.close();
}

char *DchangeB(char *buf)
{
      
    int temp[20];
 char *binary;
 int value=0,i=0,j;
 for(i=0;buf[i]!='\0';i++)
  value=value*10+(buf[i]-48);       /*将字符转化为十进制数*/
    if(value==0)
    {
  binary=new char[2];
  binary[0]='0';
  binary[1]='\0';
  return(binary);
 }
 i=0;
 while(value!=0)
    {
  temp[i++]=value%2;
  value/=2;
 }
 temp[i]='\0';
 binary=new char[i+1];
 for(j=0;j<=i-1;j++)
       binary[j]=(char)(temp[i-j-1]+48);
    binary[i]='\0';
    return(binary);  /*十进制转化为二进制*/

}

int search(char *buf,int type,int command)
{ int number=0;
    fstream outfile;
    char ch;
    char temp[30];
    int i=0;
    switch(type)
    {
 case 1: outfile.open("key.txt",ios::in);break;
    case 2: outfile.open("bsf.txt",ios::in);break;
    case 3: outfile.open("cs.txt",ios::in);break;
    case 4: outfile.open("limit.txt",ios::in);break;
    }
 outfile.get(ch);
 while(ch!=EOF){
     while(ch!='\n')
        {
            temp[i++]=ch;
            outfile.get(ch);
        }
        temp[i]='\0';
        i=0;
        number++;
        if(strcmp(temp,buf)==0)
        { 
      outfile.close();
   return number;        /*若找到,返回在相应表中的序号*/
        }
        else
          outfile.get(ch);
 }                           //结束外层while循环
     if(command==1)
     {  
      outfile.close( );
   return 0;                /*找不到,当只需查表,返回0,否则还需造表*/
    
  }
switch(type)
    {
 case 1: outfile.open("key.txt",ios::in);break;
    case 2: outfile.open("bsf.txt",ios::in);break;
    case 3: outfile.open("cs.txt",ios::in);break;
    case 4: outfile.open("limit.txt",ios::in);break;
    }
outfile<<buf;
outfile.close();
 return number+1;
}


void intdeal(char *buffer){

  fstream outfile;
    int result;
    result=search(buffer,1,1);           /*先查关键字表*/
    outfile.open("output.txt",ios::app);
    if(result!=0)
       outfile<<buffer<<result<<endl;  /*若找到,写入输出文件*/
    else
    {
        result=search(buffer,2,2);       /*若找不到,则非关键字,查标识符表,还找不到则造入标识符表*/
        outfile<<buffer<<result<<endl;
    }                                 /*写入输出文件*/
    outfile.close();
}

void chardeal(char *buffer)
{    fstream outfile;
    int result;
    result=search(buffer,1,1);           /*先查关键字表*/
 outfile.open("output.txt",ios::app);
    if(result!=0)
       outfile<<buffer<<result<<endl;   /*若找到,写入输出文件*/
    else
    {
        result=search(buffer,2,2);       /*若找不到,则非关键字,查标识符表,还找不到则造入标识符表*/
       outfile<<buffer<<result<<endl;
    }                                 /*写入输出文件*/
    outfile.close();
}

void errordeal(char error,int lineno)
{  cout<<"\nerror: "<<error<<" ,line"<<lineno;
}

void scanner()
{   fstream  infile,outfile;
    char filename[20];
    char ch;
 int err=0;
    int i=0,line=1;
    int count,result,errorno=0;
 char array[30];
    char *word;
 printf("\n please input the file scanner name:");
    scanf("%s",filename);
    err=1;
    infile.open(filename,ios::nocreate|ios::in);
    while(! infile)
    {
        cout<<"cannot open file"<<endl;
        printf("please input  the file  name again:\n");
  scanf("%s",filename);
        infile.open(filename,ios::nocreate|ios::in);
        err++;
  if(err==3)
  {cout<<"SORROY YOU CAN'T VUEW THE PRGARME\n";
        cout<<"TANKE YOU VIEW"<<endl; 
  exit(0);}
    }
    infile.get(ch);
    while(ch!=EOF)
    {                 /*按字符依次扫描源程序,直至结束*/
        i=0;
        if(((ch>='A')&&(ch<='Z'))||((ch>='a')&&(ch<='z'))||(ch=='_'))
        {           /*以字母开头*/
            while(((ch>='A')&&(ch<='Z'))||((ch>='a')&&(ch<='z'))||(ch=='_')||((ch>='0')&&(ch<='9')))
            {
                array[i++]=ch;
                infile.get(ch);
            }
            word=new char[i+1];
   memcpy(word,array,i);
   word[i]='\0';
            intdeal(word);
            if(ch!=EOF)
    infile.seekg(-1,ios::cur);
        }
        else if(ch>='0'&&ch<='9')
        {          /*以数字开头*/
            while(ch>='0'&&ch<='9')
            {
                array[i++]=ch;
                infile.get(ch);
            }
            word=new char[i+1];
   memcpy(word,array,i);
   word[i]='\0';
            intdeal(word);
            if(ch!=EOF)
    infile.seekg(-1,ios::cur);
        }
        else if((ch==' ')||(ch=='\t'))
   ;           /*消除空格符和水平制表符*/
  else if(ch=='\n')
   line++;           /*消除回车并记录行数*/
  else if(ch=='/')
        {                 /*消除注释*/
   infile.get(ch);
   if(ch=='=')
   {              /*判断是否为‘/=’符号*/
    outfile.open("output.txt",ios::noreplace|ios::app);
    outfile<<"/=\t\t\t4\t\t\t32\n";
                outfile.close();
   }
   else if(ch!='*')
            {              /*若为除号,写入输出文件*/
                outfile.open("output.txt",ios::noreplace|ios::app);
    outfile<<"/\t\t\t4\t\t\t13\n";
                outfile.close();
    outfile.seekg(-1,ios::cur);
   }
   else if(ch=='*')
   {              /*若为注释的开始,消除包含在里面的所有字符*/
    count=0;
   infile.get(ch);
    while(count!=2)
                {          /*当扫描到‘*’且紧接着下一个字符为‘/’才是注释的结束*/
     count=0;
     while(ch!='*')
      infile.get(ch);
     count++;
      infile.get(ch);
     if(ch=='/')
      count++;
     else
      infile.get(ch);
    }
   }
  }
  else if(ch=='"')
  {                 /*消除包含在双引号中的字符串常量*/
   outfile.open("output.txt",ios::noreplace|ios::app);
      outfile<<ch<<"\t\t\t4\t\t\t37\n";
   outfile.close();
   while(ch!='"')
   infile.get(ch);
            infile<<ch<<"\t\t\t4\t\t\t37\n";
   infile.close();
  }
  else
        {         /*首字符为其它字符,即运算限界符或非法字符*/
            array[0]=ch;
            infile.get(ch);       /*再读入下一个字符,判断是否为双字符运算、限界符*/
            if(ch!=EOF)
            {           /*若该字符非文件结束符*/
                array[1]=ch;
    word=new char[3];
    memcpy(word,array,2);
    word[2]='\0';
                result=search(word,4,1);      /*先检索是否为双字符运算、限界符*/
    if(result==0)
    {                           /*若不是*/
                    word=new char[2];
     memcpy(word,array,1);
     word[1]='\0';
     result=search(word,4,1);      /*检索是否为单字符运算、限界符*/
     if(result==0)
                    {                           /*若还不是,则为非法字符*/
      errordeal(array[0],line);
      errorno++;
      infile.seekg(-1,ios::cur);
                    }
                    else
     {     /*若为单字符运算、限界符,写入输出文件并将扫描文件指针回退一个字符*/
      outfile.open("output.txt",ios::noreplace|ios::app);
      outfile<<word<<"\t\t\t4\t\t\t"<<result<<"\t"<<endl;
      outfile.close();
      infile.seekg(-1,ios::cur);
     }
    }
                else
    {             /*若为双字符运算、限界符,写入输出文件*/
     outfile.open("output.txt",ios::noreplace|ios::app);
        outfile<<word<<"\t\t\t4\t\t\t"<<result<<endl;;
     outfile.close( );
    }
            }
            else
   {               /*若读入的下一个字符为文件结束符*/
    word=new char[2];
    memcpy(word,array,1);
    word[1]='\0';
    result=search(word,4,1);       /*只考虑是否为单字符运算、限界符*/
    if(result==0)                /*若不是,转出错处理*/
     errordeal(array[0],line);
    else
    {                            /*若是,写输出文件*/
     outfile.open("output.txt",ios::noreplace|ios::app);
        outfile<<word<<"\t\t\t4\t\t\t"<<result<<"\t"<<endl;
     outfile.close();
    }
   }
        }
        infile.get(ch);
    }
    infile.close();
cout<<"\nThere are "<<errorno<<" error(s).\n";         /*报告错误字符个数*/
}
void main()
{   char yn;
 
 do{
    init(); /*初始化*/
    scanner();/*扫描源程序*/

 printf("Are You continue(y/n)\n"); //判断是否继续?
 yn=getch();
 }while(yn=='y'||yn=='Y');
}

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