cifafenxi.cpp

PASCAL词法分析返回类号PASCAL词法分析返回类号

#include <stdio.h>
#include <io.h>
#include <ctype.h>
#include <malloc.h>//源代码有错
#include <stdlib.h>
#include <string.h>
//===========================================================
#define  NULL 0
FILE *fp;	 FILE *infile;
char cbuffer;
char *key[21]={"and","begin","const","div","do","else","end",
	       "function","if","integer","not","or","procedure",
	       "program","read","real","then","type","var","while",
	       "write"};//1
char *border[8]={",",";",":",".","(",")","[","]"};//2
char *arithmetic[4]={"+","-","*","/"};//3
char *relation[10]={"=","<",">","<>","<=",">=",":=","{","}","#"};//4
char *consts[20];//5
char *label[20];//6
int constnum=0,labelnum=0;
//===========================================================
int search(char searchchar[],int wordtype)//查找保留字
     {
     int i=0;
     switch (wordtype) {
	 case 1:{for (i=0;i<=20;i++)
			  {
		          if (strcmp(key[i],searchchar)==0)
                 	return(i);
			  };break;
			}//原代码有错
      case 2:{for (i=0;i<=7;i++)//查找界符
			  {
		          if (strcmp(border[i],searchchar)==0)
		            return(i+23);
			  };break;
			  }
      case 3:{for (i=0;i<=3;i++)//查找运算符
			  {
		          if (strcmp(arithmetic[i],searchchar)==0)
		            return(i+34);
		      };break;
			  }
       case 4:{for (i=0;i<=9;i++)//查找关系运算符
			  {
		          if (strcmp(relation[i],searchchar)==0)
		            return(i+38);
			  };break;
			  }
       case 5:{for (i=0;i<=constnum;i++)
			  {
		          if (strcmp(consts[i],searchchar)==0)
		            return(22);
		      }
	         consts[i-1]=(char *)malloc(sizeof(searchchar));
	         strcpy(consts[i-1],searchchar);
	         constnum++;
			  }//数字
       case 6:{for (i=0;i<=labelnum;i++)
			  {
		        if (strcmp(label[i],searchchar)==0)
			        return(21);
			  }
	          label[i-1]=(char *)malloc(sizeof(searchchar));
	          strcpy(label[i-1],searchchar);
	          labelnum++;
	          return(i); 
			  }//标识符
		   }
 }//======================================
char alphaprocess(char buffer)
     { 
      int atype;
      int i=-1;
      char alphatp[20];
      while ((isalpha(buffer))||(isdigit(buffer)))
        { alphatp[++i]=buffer;
         buffer=fgetc(fp);
        }
      alphatp[i+1]='\0';
      if (atype=search(alphatp,1))
     printf("%s  ,  %d\n",alphatp,atype);
      else   
	  {
		  atype=search(alphatp,6);
          printf("%s   ,  %d\n",alphatp,atype);
       }
      return(buffer);
      }//关键字标识符识别,原代码有误
//=========================================
char digitprocess(char buffer)
     {
      int i=-1;
      char digittp[20];
      int dtype;
      while ((isdigit(buffer)))
	    {
	    digittp[++i]=buffer;
	    buffer=fgetc(fp);
	    }
      digittp[i+1]='\0';
      dtype=search(digittp,5);
      printf("%s  ,  %d\n",digittp,22);
      fprintf(infile, "%s  ,  %d\n",digittp,22);//不规范调试
      return(buffer);
     }
//==========================================
char otherprocess(char buffer)//重写完成
     {
      char othertp[20];
if (isspace(buffer)!=0)
 {
  buffer=fgetc(fp);
  goto out;
 }//此段代码用于消除空格，原代码没有。
      int otype,otypetp;
      othertp[0]=buffer;
      othertp[1]='\0';
      if (buffer=='+'||buffer=='-'||buffer=='*'||buffer=='/')
	 {
		  otype=search(othertp,3);
	 printf("%s  ,  %d\n",othertp,otype);
     fprintf(infile,"%s  ,  %d\n",othertp,otype);
	 buffer=fgetc(fp);
	 goto out;
	 };
      if (buffer=='='||buffer=='<'||buffer=='>'||buffer=='{'||buffer=='}')
	  {
		  otype=search(othertp,4);
		printf("%s  ,   %d\n",othertp,otype);
       fprintf(infile,"%s  ,   %d\n",othertp,otype);
	   buffer=fgetc(fp);
		 goto out;
	      };
      if(buffer==':')
	      {
	      buffer=fgetc(fp);
		  if (buffer=='='){
		 printf(":=    ,   44\n");
		 fprintf(infile,":=    ,   44\n");
		 buffer=fgetc(fp);}
		  else
		  {
			  printf(":    ,   25\n");
		 fprintf(infile,":    ,   25\n");
		  }
		 goto out;
	      };
	  if (buffer==','||buffer==';'||buffer=='.'||buffer=='('||buffer==')'||buffer=='['||buffer==']')
		 {
		  otype=search(othertp,2);
		 printf("%s  ,   %d\n",othertp,otype);
        fprintf(infile,"%s  ,   %d\n",othertp,otype);
		 buffer=fgetc(fp);
		 goto out;
		 };
	  if ((buffer!='\n')&&(buffer!=' '))
		  {
          printf("%c error,not a word\n",buffer);
          fprintf(infile,"%c error,not a word\n",buffer);
         }
  buffer=fgetc(fp);
out:      return(buffer);
     }
//=============================================
void main()
{
     int i;
     printf("     The Result :\n");
     for (i=0;i<=20;i++)
	 {
	   label[i]="";
	   consts[i]="";//原代码会引起指针错误
	 }
	 infile=fopen("result.txt","w");
     if ((fp=fopen("pas.txt","r"))==NULL)
	    printf("error");
     else
	  {
    	cbuffer = fgetc(fp);
    	while (cbuffer!=EOF)
		{
	      if (isalpha(cbuffer))//测试是否英文字母
	         cbuffer=alphaprocess(cbuffer);//关键字和标识符处理函数
     	  else if (isdigit(cbuffer))//是否数字
	         cbuffer=digitprocess(cbuffer);//数字处理函数
	      else cbuffer=otherprocess(cbuffer);//其它处理
		}
     	 printf("     OVER !\n");
         fprintf(infile, "     OVER !\n");
	 }
}