word.cpp

用c++ 编写的词法编辑器

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<ctype.h>
#include<malloc.h>
#include<conio.h>
#define true  1
#define false 0

typedef struct kinds{
    int code;
    int value;
};

char word[80];  //put word
int base=0;
int search=0;
char* reserveWord[]={ "if","then","else", "while", "do" };

char getOneChar(){
  char ch;
  ch=word[base];
  base++;
  return ch;
}

void retract(){
  base--;
}
int reserve(char *token){
   int i=0;
   int j=0;
   for(i=0;i<4;i++){
     j=strcmp(token,reserveWord[i]);
     if(j==0) return true;
   }
   return false;
}

kinds scan(void){

   kinds kind;
   int i=0;
   int number;
   char ch;
   char *token;
   token=(char *)malloc(20);
   //token="";
  // while( (ch=getOneChar())==' ')
     ch=getOneChar();

   if(isalpha(ch)){              //letter
      //printf("\nttt %c",ch);
     while(isalpha(ch)||isdigit(ch) ){
       //strcat(token,ch);
       token[i]=ch;
       token[i+1]='\0';
	i++;
       ch=getOneChar();
     }
     retract();
     kind.code=reserve(token);   //reserveWord,  code=1
     if(kind.code==0){           //not reserveWord
       printf("\nIDN %8s",token); return kind;
     }
     else{
       printf("\n%s         _",token);   //?????????
       return kind;
     }

   }
   /* shu zi */
   else if(isdigit(ch)){
     if(ch=='0'){
       ch=getOneChar();
       if(ch=='x'||ch=='X'){
	 ch=getOneChar();
	 if(ch>='0'&&ch<='9'||ch>='a'&&ch<='f'){
	   while(ch>='0'&&ch<='9'||ch>='a'&&ch<='f'){
	     token[i]=ch;
	     token[i+1]='\0';
	     i++;
	     ch=getOneChar();
	   }
	   retract();
	   sscanf(token,"%x",&number);
	   printf("\nINT16     %d",number);
	   return kind;   //????????????
	 }
	 else{
	   printf("???????? 0x ??????");
	 }
       }
       else if(ch>='0'&&ch<='7'){
	 while(ch>='0'&&ch<='7'){
	     token[i]=ch;
	     token[i+1]='\0';
	     i++;
	     ch=getOneChar();
	   }
	   retract();
	   sscanf(token,"%o",&number);
	   printf("\nINT8      %d",number);
	   return kind;   //????????????

       }
       else{
	 retract();
	 //printf("\nINT10     %s",token);
	 printf("\nINT10    0");
	 return kind;   //????????????
       }
     }
     else{   //ch== 1--9
       while(ch>='0'&&ch<='9'){
	     token[i]=ch;
	     token[i+1]='\0';
	     i++;
	     ch=getOneChar();
	   }
	   retract();
	   printf("\nINT10      %s",token);
	   return kind;   //????????????
     }
   }
   else if(ch=='+'){
     printf("\n+        _ ");
     return kind;
   }
   else if(ch=='-'){
     printf("\n-        _ ");
     return kind;
   }
   else if(ch=='*'){
     printf("\n*        _ ");
     return kind;
   }
   else if(ch=='/'){
     printf("\n/        _ ");
     return kind;
   }
   else if(ch=='='){
     printf("\n=        _ ");
     return kind;
   }
   else if(ch=='<'){
     printf("\n<        _ ");
     return kind;
   }
   else if(ch=='>'){
     printf("\n>        _ ");
     return kind;
   }
   else if(ch==' '){return kind;}
   else{ //wrong!
       printf("\nI don't know! ");
   }

   //kind.code=1;
   kind.value=0;
   free(token);
   return kind;
}

void main(){
   kinds kind;
   int i=0;

   clrscr();
   gets(word);
   //printf("%s",word);
   while(base<strlen(word)){
     kind=scan();
    // printf("\n kind: %d , %d; base:%d ",kind.code,kind.value,base);
   }
   getch();
   return;
}