zq.cpp

分析器 用c语言编写的 已经运行通过的 供给大家参考

#include <stdio.h>
#include <ctype.h>
#include <malloc.h>
#include <stdlib.h>
#include <string.h>
#define NULL 0

FILE *fp;//源文件指针
char cbuffer;
char *keyword[4]={"IF","THEN","ELSE","GOTO"};//关键字
char *border[6]={",",";",":=",".","(",")"};//指针数组，用于指向符号表；
char *arithmetic[4]={"+","-","*","/"};//指针数组，指向算术运算符表；
char *relation[6]={"<","<=","=",">",">=","<>"};//指针数组，指向关系运算符表；
char *consts[20];//指针数组，指向常数表；
char *label[20];//指针数组，指向标识符表；
int constnum=0,labelnum=0;//整型变量，分别用于存放当前常数个数和标识符个数。

int search(char searchchar[],int wordtype)//查找单词种别函数
     {
     int i=0;
     switch (wordtype) {
       case 1:for (i=0;i<=7;i++)
		  {
		   if (strcmp(keyword[i],searchchar)==0)
		     return(i+1);
		  };

       case 2:{for (i=0;i<=5;i++)
		  {
		   if (strcmp(border[i],searchchar)==0)
		      return(i+1);
		  };
	       return(0);
	      }

       case 3:{for (i=0;i<=3;i++)
		  {
		   if (strcmp(arithmetic[i],searchchar)==0)
		      {
		       return(i+1);
		      };
		  };
	      return(0);
	      };

       case 4:{for (i=0;i<=5;i++)
		  {
		   if (strcmp(relation[i],searchchar)==0)
		      {
		       return(i+1);
		      };
		  };
	       return(0);
	      };

       case 5:{for (i=0;i<=constnum;i++)
		  {
		   if (strcmp(consts[i],searchchar)==0)
		       {
			return(i+1);
		       };
		  }
	      consts[i-1]=(char *)malloc(sizeof(searchchar));
	      strcpy(consts[i-1],searchchar);
	      constnum++;
	      return(i);
	      };

       case 6:{for (i=0;i<=labelnum;i++)
		  {
		     if (strcmp(label[i],searchchar)==0)
		       {
			return(i+1);
		       };
		  }
	      label[i-1]=(char *)malloc(sizeof(searchchar));
	      strcpy(label[i-1],searchchar);
	      labelnum++;
	      return(i);
	      };

      }


     }


char alphaprocess(char buffer)
     {
      int atype;
      int i=-1;
      char alphatp[20];
      while ((isalpha(buffer))||(isdigit(buffer)))
	    {
	    alphatp[++i]=buffer;//相当于送入临时数组alphatp[0]；
	    buffer=fgetc(fp);//再读入一个字符至buffer；
	    };
      alphatp[i+1]='\0';//重复上面两步，直到后一步判断为假；在alphatp末尾添加'\0'；
      if (atype=search(alphatp,1))//调用search()子函数，在关键字表中匹配alphatp，若匹配成功，则返回序号；
	 printf("%s (1,%d)\n",alphatp,atype-1);
      else
	 {
	 atype=search(alphatp,6);//调用search，在标识符表中匹配alphatp，若匹配成功，则返回序号；
	 printf("%s (6,%d)\n",alphatp,atype-1);//在标识符表中添加alphatp，并返回序号；
	 };
      return(buffer);
      }

char digitprocess(char buffer)//数字处理函数；
     {
      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 (5,%d)\n",digittp,dtype-1);
      return(buffer);
     }

char otherprocess(char buffer)
     {

      int i=-1;
      char othertp[20];
      int otype,otypetp;
      othertp[0]=buffer;
      othertp[1]='\0';
      if (otype=search(othertp,3))
	 {
	 printf("%s (3,%d)\n",othertp,otype-1);
	 buffer=fgetc(fp);
	 goto out;
	 };

      if (otype=search(othertp,4))
	      {
	      buffer=fgetc(fp);
	      othertp[1]=buffer;
	      othertp[2]='\0';
	      if (otypetp=search(othertp,4))
		 {
		 printf("%s (4,%d)\n",othertp,otypetp-1);
		 goto out;
		 }
	      else
		 othertp[1]='\0';
		 printf("%s (4,%d)\n",othertp,otype-1);
		 goto out;
	      };

      if (buffer==':')
	      {
	      buffer=fgetc(fp);
	      if (buffer=='=')
		 printf(":= (2,2)\n");
		 buffer=fgetc(fp);
		 goto out;
	      }
	   else
	      {
	      if (otype=search(othertp,2))
		 {
		 printf("%s (2,%d)\n",othertp,otype-1);
		 buffer=fgetc(fp);
		 goto out;
		 }
	      };

	  if ((buffer!='\n')&&(buffer!=' '))
		  printf("%c error,not a word\n",buffer);
	  buffer=fgetc(fp);
out:      return(buffer);
     }



void main()
     {
     int i;
      for (i=0;i<=20;i++)
	  {
	   label[i]=NULL;
	   consts[i]=NULL;
	  };
      if ((fp=fopen("source.txt","r"))==NULL)
	 printf("打不开 或者是错了 ");
      else
	{
	cbuffer = fgetc(fp); //读入一个字符ch
	while (cbuffer!=EOF)
	 {
	  if (isalpha(cbuffer))
	     cbuffer=alphaprocess(cbuffer);//关键字和标识符处理子函数；
	  else if (isdigit(cbuffer))
	     cbuffer=digitprocess(cbuffer);//数字处理
	  else cbuffer=otherprocess(cbuffer);//其它字符处理
	  };
	 printf("over\n");
	 };
      }