#include <iostream>
#include <thread>
#include <mutex>
#include <vector>

class BankAccount {
private:
    double balance;
    std::mutex mtx;  // 互斥锁

public:
    BankAccount(double initial) : balance(initial) {}

    void deposit(double amount) {
        std::lock_guard<std::mutex> lock(mtx);  // 自动加锁
        balance += amount;
        std::cout << "Deposited " << amount 
                  << ", new balance: " << balance << std::endl;
    }

    void withdraw(double amount) {
        std::lock_guard<std::mutex> lock(mtx);
        if (balance >= amount) {
            balance -= amount;
            std::cout << "Withdrew " << amount 
                      << ", new balance: " << balance << std::endl;
        } else {
            std::cout << "Failed to withdraw " << amount 
                      << ", insufficient funds" << std::endl;
        }
    }

    double get_balance() const {
        std::lock_guard<std::mutex> lock(mtx);
        return balance;
    }
};

void worker(BankAccount& account) {
    for (int i = 0; i < 5; ++i) {
        account.deposit(100);
        account.withdraw(50);
    }
}

int main() {
    BankAccount account(1000);
    std::vector<std::thread> threads;

    // 创建 3 个线程同时操作账户
    for (int i = 0; i < 3; ++i) {
        threads.emplace_back(worker, std::ref(account));
    }

    for (auto& t : threads) {
        t.join();
    }

    std::cout << "Final balance: " << account.get_balance() << std::endl;
    return 0;
}