12. Lex program to put every line in parenthesis

The program puts every line in parenthesis.
For example

I am going
We are going

appears

{I am going}
{We are going}

Here is the code :

%{
   
%}
%%
[a-z A-Z]+ {printf("{%s}",yytext);}
%%

main()
{
extern FILE *yyin;
yyin=fopen("new","r");
yylex();
}