访问派生类中的受保护成员

class Base {
    protected int x;

    public Base(int x) {
        this.x = x;
    }
}

class Derived extends Base {
    public Derived(int x) {
        super(x);
    }

    public void printX() {
        System.out.println("x = " + x);
    }
}

public class Main {
    public static void main(String[] args) {
        Derived d = new Derived(10);
        d.printX(); // 输出：x = 10
    }
}