The second place where you used Person for declaration looks as follows under the effect of typedef........

Person
{
char name[11];
int age ;
};


looks like-------------->

struct Person {} {
char name[11];
int age ;
};

Coz, Person is of type 'struct Person' which is empty structure..........Try above syntax, YOU WILL DEFINETLY GET THE SAME ERROR AND CONCLUDE YOURSELF THE WORKING OF "TYPEDEF"