Java 문법 통합 실습

import java.util.*;
import java.util.stream.*;

interface Transferable {
    boolean transfer(Account to, int amount);
}

class Account implements Transferable {
    private final String id;
    private String owner;
    private int balance;

    public Account(String id, String owner, int balance) {
        this.id = id; this.owner = owner; this.balance = balance;
    }

    @Override
    public boolean transfer(Account to, int amount) {
        if (this.balance < amount) return false;
        this.balance -= amount;
        to.balance += amount;
        return true;
    }

    public int getBalance() { return balance; }
    public String getOwner() { return owner; }
    public String toString() { return owner + ": " + balance + "원"; }
}

public class BankSystem {
    public static void main(String[] args) {
        List<Account> accounts = Arrays.asList(
            new Account("A001", "Alice", 500000),
            new Account("A002", "Bob", 300000),
            new Account("A003", "Charlie", 100000)
        );

        accounts.get(0).transfer(accounts.get(2), 200000);

        accounts.stream()
            .sorted((a, b) -> b.getBalance() - a.getBalance())
            .forEach(System.out::println);
    }
}