Dealing with operator overload method as a friend - c++

Question

I tried to create simple class and to overload some of it's operators, however, i failed at the very beginning, here's my code:
#include <iostream>
class Person
{
char *firstName;
char *lastName;
int age;
friend std::ostream &operator<<(std::ostream &, const Person &);
public:
Person() : firstName("Piotr"), lastName("Tchaikovsky"), age(10) {}
Person(char* f, char* l, int a)
{
this->firstName = f;
this->lastName = l;
age = a;
}
std::ostream &operator<<(std::ostream& out, const Person &p)
{
out << p.firstName << " " << p.lastName;
return out;
}
};
int main()
{
Person a;
getchar();
getchar();
}
So, before i created this operator overloading function i used debugger to see if constructor is going to work, and it worked, since default values were given correctly to the variable a i created, after that, all i did was that i created function that overloads the operator << and it is a friend function of my class, since i am taught that it is a good thing to do due to the type of the first parameter of overloading function, however, when i try to run this (NOTE: i have not tried to print out anything yet, i wanted to check if everything works fine first) it gives me errors saying:
"too many parameters for this operator function",
"binary 'operator <<' has too many parameters" and
" 'Person::operator<<' :error in function declaration; skipping function body"
however, i can't find any problems with function declaration, and i cannot possibly see how two parameters can be too many for this function. Any help appreciated!

Answer 1

You declare the friend function as a global non-member function. Then you define a member function.
Move the definition of the operator<< function to outside the class:
class Person
{
...
friend std::ostream &operator<<(std::ostream &, const Person &);
...
};
std::ostream &operator<<(std::ostream& out, const Person &p)
{
out << p.firstName << " " << p.lastName;
return out;
}
Or alternatively define the friend function inline:
class Person
{
...
friend std::ostream &operator<<(std::ostream &, const Person &)
{
out << p.firstName << " " << p.lastName;
return out;
}
...
};