accidence.cpp

计算机专业编译原理课程设计源代码！！ 编译器

#include<stdio.h>
#include<string.h>
#include<stdlib.h> 
#include<ctype.h>
#include<iostream.h>
#include<windows.h>

//FILE *tokenfout;
/*typedef struct token
{
	char *name;
    int code;
}token;
 
token mytoken[50];*/

typedef struct keyword
{
	char *name;
    int code;
}keyword;

keyword key[7]={{"if",3},{"then",4},{"else",5},{"while",6},{"do",7},{"begin",8},{"end",9}};




#define ID 1
#define INT 2
#define ADD 10
#define MIN 11
#define MUL 12
#define DIV 13
#define LT 14
#define LE 15
#define EQ 16
#define GE 17
#define GT 18
#define NE 19
#define EVA 20
#define LP 21
#define RP 22
#define SEM 23

FILE *in;
char token[50];
int error_count=0;
int k,b;
char ch1;
int row=0;
int queue=0;

void report_error(int a)
{error_count++;
 switch(a)
 {
 case 1:cout<<"标识符长度超过６，不合法"<<"   "<<"行"<<row<<","<<"列"<<queue<<endl;break;
 case 2:cout<<"非法字符"<<"   "<<"行"<<row<<","<<"列"<<queue<<endl;break;
 case 3:cout<<"数值超过最大表示范围,溢出"<<"   "<<"行"<<row<<","<<"列"<<queue<<endl;break;
 case 4:cout<<"没有匹配的注释符 '*/' "<<"   "<<"行"<<row<<","<<"列"<<queue<<endl;break;
 case 5:cout<<"标识符以数字开头，不合法"<<"   "<<"行"<<row<<","<<"列"<<queue<<endl;break;
 }
}

void out(char *t,int s)
{

	    cout<<"("<<t<<" , "<<s<<")"<<"   "<<"行"<<row<<","<<"列"<<queue<<endl;

}





int lookup(char *c)
{

    int h=1;
	for(int i=0;i<7;i++)
	if((h=strcmp(c,key[i].name))==0) break;
     if(h) return -1;
     if(!h)
	 return i;
 }


void scanner()
{char ch;
 int i=0,c;
 
 while((ch=fgetc(in))!=EOF)
 {   
	 if(isalpha(ch))
	 {
		 token[0]=ch;
         ch=fgetc(in);i=1;
   while(isalnum(ch))
   {
	   token[i]=ch;i++;
       ch=fgetc(in);
   }
   token[i]='\0';
   fseek(in,-1,1);
   c=lookup(token);
   if(c==-1)	   
	   if((k=strlen(token))<7)
	   out(token,ID);
       
	   else report_error(1);
	        
	   else out(key[c].name,key[c].code);
	            
	 

	}

  else 
	  if(isdigit(ch))
	  {
		  token[0]=ch;
	      ch=fgetc(in);i=1;
	   while(isdigit(ch))
	   {
		   token[i]=ch;i++;
	       ch=fgetc(in);
	   }
	   
        if(isalpha(ch))
		{
			token[i]=ch;
			i++;
			ch=fgetc(in);
				while(isalnum(ch))
					{
						token[i]=ch;
				        i++;
				        ch=fgetc(in);
					}
				token[i]='\0';
				fseek(in,-1,1);
		report_error(5);		
	   }
		else{
		
	   token[i]='\0';
       fseek(in,-1,1);
	   b=atoi(token);
	   if((b<=65535)&&(b>=0))
	    out(token,INT);
	    
	    else if(b>65535) report_error(3);
		}                
	  }
  else
	  switch(ch)
  {
   case'<':ch=fgetc(in);
          if(ch=='=')
		  out("<=",LE);
		       
		  else if(ch=='>')
		   out("<>",NE);
		     
		  else {fseek(in,-1,1);
		   out("<",LT);
             
		  }
		  break;
   case'=':out("=",EQ);
	       
	        break;
   case'>':ch=fgetc(in);
	         if(ch=='=')
			 out(">=",GE);
                 
			 else{fseek(in,-1,1);
			      out(">",GT);
			 }
			 break;
   case'+':out("+",ADD);
	          break;
   case'-':out("-",MIN);
	        break;
   case'*':out("*",MUL);
	        break;
   case'/': ch=fgetc(in);
       if(ch=='*') 
	   { for(;;)
	   { ch=fgetc(in);
       if(ch==EOF)
	   { report_error(4);
        break;
	   }
         if(ch=='*')
		 { ch1=ch;
         ch=fgetc(in);
         if(ch=='/')
		 { ch=fgetc(in);break;
		 }
		 }
	   }
	   }
	   
   else out("/",DIV);
         break;
   
   case':':ch=fgetc(in);
	      if(ch=='=')
		  out(":=",EVA);
		  break;
   case'(':
	      out("(",LP);
		  break;
   case')':
	      out(")",RP);
		  break;
   case';':
	      out(";",SEM);
		  break;
   case' ':queue++;break;
   case'\t':break;	      
   case'\n':row++;break;
	        
   default:report_error(2);
	       break;
  }
  
 }
  return;
 }

void main()
{   
	char filename[30];
	cout<<"please input your filename"<<endl;
    cin>>filename;
    if((in=fopen(filename,"rt"))==NULL)
	{
		printf("cannot open the file %s.\n",filename);
        exit(1);
	}


  
  scanner();
  cout<<"**********************************************"<<endl;
  cout<<endl;
  cout<<"错误个数"<<" "<<error_count<<endl;endl;

  //if((tokenfout=fopen("token.txt","wt+"))==NULL)
  //{cout<<"无法打开文件 token.txt"<<endl;
   //exit(1);
  //}  
  
}