使用帳戶存款與顯示餘額來解釋 物件 & 類別 相依關係

Object and Class

class UserAccount {
    private int balance = 0; // 帳戶餘額，初始為0

    // 清空帳戶餘額
    public void clearAccount() {
        balance = 0;
    }

    // 存款
    public void deposit(int amount) {
        balance += amount; // balance = balance + amount
    }

    // 查詢目前餘額
    public int getBalance() {
        return balance;
    }
}

public class Person {
    public static void main(String[] args) {
        // 建立兩個帳戶
        UserAccount apple = new UserAccount();
        UserAccount android = new UserAccount();

        // 操作帳戶
        apple.deposit(1500);
        android.deposit(2200);

        // 顯示帳戶餘額
        System.out.println("Apple has " + apple.getBalance() + " dollars.");
        System.out.println("Android has " + android.getBalance() + " dollars.");
    }
}