C/C++ :: How To Declare Global Variable In Structure

I am getting this error while trying to compile my program:

It says that my variables "nome, cognome, eta..etc" are being used for the first time in my "inserisci" function.

I tought that I could just declare them as global in my structure like I did in my code, but apparently this doesn't work.

Do I really need to declare them again outside of my structure? Isn't there another way?

Here is my code:

#include <stdio.h>
#include "readline.h"
void inserisci(void);
struct impiegato{
char nome[20];
char cognome[20];
int eta;

[code].....