%{
  #include<stdio.h>
  
%}
%%
[a-zA-Z_][a-zA-Z0-9_]*       {printf("%s is an identifier");}
[+-]?[0-9]+                  {printf("%s is a signed number ");}
[0-9]+                       {printf("Rejected");}
%%
int main(){
  printf("enter:");
  yylex();
  
}
int yywrap(){
  return 1;
}