Classes & Objects

#include <iostream>
#include <string>
using namespace std;

class BankAccount {
private:
    string owner;
    double balance;
    int id;
    static int nextId;

public:
    // Constructor with initializer list
    BankAccount(const string &owner, double initialBalance = 0.0)
        : owner(owner), balance(initialBalance), id(nextId++) {}

    // Copy constructor
    BankAccount(const BankAccount &other)
        : owner(other.owner), balance(other.balance), id(nextId++) {}

    // Destructor (called when object goes out of scope)
    ~BankAccount() {
        cout << "Account #" << id << " closed" << endl;
    }

    // Getters
    double getBalance() const { return balance; }
    string getOwner() const { return owner; }

    // Methods
    void deposit(double amount) {
        if (amount > 0) balance += amount;
    }

    bool withdraw(double amount) {
        if (amount > 0 && amount <= balance) {
            balance -= amount;
            return true;
        }
        return false;
    }

    // Operator overloading
    BankAccount operator+(const BankAccount &other) const {
        return BankAccount(owner + " & " + other.owner, balance + other.balance);
    }

    bool operator>(const BankAccount &other) const {
        return balance > other.balance;
    }

    // Friend function (access private members)
    friend ostream &operator<<(ostream &os, const BankAccount &acc) {
        os << "[#" << acc.id << "] " << acc.owner << ": $" << acc.balance;
        return os;
    }
};

int BankAccount::nextId = 1;

int main() {
    BankAccount alice("Alice", 1000);
    BankAccount bob("Bob", 500);

    alice.deposit(250);
    bob.withdraw(100);

    cout << alice << endl;  // Operator<< overload
    cout << bob << endl;

    if (alice > bob) cout << "Alice has more" << endl;

    // RAII: accounts automatically destroyed at end of scope
    return 0;
}