No match for operator << in exception handling program - c++

Question

#include <iostream>
#include <string>
#include "NegativeBalanceException.hpp"
#include <memory>
class Account
{
private:
std::string name;
double balance;
public:
Account(std::string name, double balance);
~Account() {std::cout <<"Calling Account Destroyer" << std::endl;}
void get_name() const {std::cout << name << std::endl;}
void get_balance() const {std::cout << balance << std::endl;}
friend std::ostream &operator<<(std::ostream &os, const Account &account);
};
Account::Account(std::string name, double balance)
: name{name}, balance{balance} {
if (balance < 0)
throw NegativeBalanceException();
}
std::ostream &operator<<(std::ostream &os, const Account &account) {
os << "Account Name: " << account.get_name() << "\n" << "Account
Balance: " << account.get_balance() << std::endl;
return os;
}
int main () {
std::unique_ptr<Account> Austin;
try {
Austin = std::make_unique<Account>("Austin",1000);
std::cout << *Austin << std::endl;
}
catch (const NegativeBalanceException &ex) {
std::cerr << ex.what() << std::endl;
}
};
Hello I am a beginner programmer and I am practicing exception handling and I do not know why my overloaded operator << is not working. It won't let me display my data that I want.

Answer 1

Your get_name() and get_balance() methods are both declared with void return values, so your overloaded operator<< can't pass them to os << .... Internally, the methods are doing their own logging to std::cout, so you would need to change your operator<< accordingly, eg:
std::ostream &operator<<(std::ostream &os, const Account &account) {
os << "Account Name: ";
account.get_name();
os << "Account Balance: ";
account.get_balance();
return os;
}
However, this will not work as expected if os does not refer to std::cout, for example if your main() decided to stream the Account to a std::ofstream instead.
A better option is to change get_name() and get_balance() to return values instead, and not do their own logging directly:
std::string get_name() const { return name; }
double get_balance() const { return balance; }
Then your overloaded operator<< will work as expected.

Answer 2

These
void get_name() const {std::cout << name << std::endl;}
void get_balance() const {std::cout << balance << std::endl;}
should be written like this
std::string get_name() const { return name; }
double get_balance() const { return balance; }
Functions which return values are not the same as functions which print values. In your overloaded operator<< you need two functions to return the values in the account object, so the operator<< can print them.