title: Unknown character error in bison
body: <p>I write a parser by bison , when I type this command in Ubuntu </p>
  
  <pre><code> bison bison.txt
  </code></pre>
  
  <p>It returns these errors :</p>
  
  <pre>
      Inspiron-N5110:~/Desktop/BisonProject$ bison bison.txt
      "bison.txt",  line 10: unknown character with code 0xd in declaration section
      "bison.txt", line 10: no input grammar
      *** Error in `bison': double free or corruption
      (!prev): 0x0000000000915780 *** Aborted (core dumped)
  </pre>
  
  <p>bison.txt : </p>
  
  <pre><code>%{ 
  #include &lt;ctype.h&gt; 
  #include &lt;stdio.h&gt;
  #include &lt;stdlib.h&gt;
  #include &lt;conio.h&gt;
  #include "lex.yy.c"
  void yyerror(char *);
  extern FILE* yyin;
  extern char* yytext;
  %} 
  
  %token int_kw void_kw bool_kw open_bracket close_bracket number semicolon ID comma
  %start Program
  
  %%
  Program:
      DeclarationList;
  
  DeclarationList:
      DeclarationList Declaration | Declaration;
  
  Declaration:
      VarDeclaration;
  
  VarDeclaration:
      TypeSpecifier VarDecList;
  
  VarDecList:
      VarDecList comma VarDecId | VarDecId;
  
  VarDecId:
      ID | ID open_bracket number close_bracket  ;
  
  TypeSpecifier:
      int_kw | void_kw | bool_kw;
  
  %%
  
  int main(){
    char fname[50];
    printf("Enter the name of your file:\n");
    scanf("%s",fname);
  
    fopen(fname,"r");
  
    yyparse();
    return 0;
  }
  
  void yyerror(char *s1){
    printf("%s\n",s1);
    return;
  }
  </code></pre>