%{
#include<stdio.h>
%}
%option noyymrap
%%
[\t\n]+ {/*ignore whitespace*/}
"int"|"float"|"else"|"whie"|"{printf("keyword:%s\n",yytext);}
[0-9]+ {printf("integer constant:%s\n",yytext);}
[0-9]*","[0-9]+ {printf("float constant:%s\n",yytext);}
"//",* {printf("single-line comment\n");}
"^*"[^*]*"\*/" {printf("multi-line comment\n");}
[a-zA-Z_][a-zA-Z0-9_]*{printf("identifer:%s\n",yytext);}
"=="|"!"|"<"|"="|"+"|"-"|"*"|"/" {printf("operator:%s\n",yytext);}
.	
{printf("unknown token":%s\n",yytext);}
%%
int main(){
print("enter input:");
yylex();
return 0;
}