It comes declaration syntax error after i save my file as header file

Question

before saving there was no error but after I saved file as header file with extension .h

//password.h

#ifndef PASSWORD_H
#define PASSWORD_H

class password
{
char buffer[20];
public:
int checkpd(char *);
};

#endif

Answer 1

char buffer[20]; may need to be made public

Answer 2

but it's not necessary
we can declare it anywhere I think