类内函数

   创建了一个名为MyClass的类，并在其中实现了默认构造函数、参数化构造函数、拷贝构造函数、移动构造函数、析构函数、拷贝赋值运算符、移动赋值运算符、成员函数、静态成员函数和友元函数。在主函数中，我们创建了几个类对象，并演示了这些函数的调用和使用。请注意，输出语句被添加到每个函数的实现中，以便在调用时打印出相应的消息，以便我们可以清楚地看到每个函数的调用顺序

class MyClass {
public:
    int value;

    // Default constructor
    MyClass() {
        value = 0;
        cout << "Default constructor called" << endl;
    }

    // Parameterized constructor
    MyClass(int val) {
        value = val;
        cout << "Parameterized constructor called" << endl;
    }

    // Copy constructor
    MyClass(const MyClass& other) {
        value = other.value;
        cout << "Copy constructor called" << endl;
    }

    // Move constructor
    MyClass(MyClass&& other) noexcept {
        value = other.value;
        cout << "Move constructor called" << endl;
    }

    // Destructor
    ~MyClass() {
        cout << "Destructor called" << endl;
    }

    // Copy assignment operator
    MyClass& operator=(const MyClass& other) {
        if (this != &other) {
            value = other.value;
        }
        cout << "Copy assignment operator called" << endl;
        return *this;
    }

    // Move assignment operator
    MyClass& operator=(MyClass&& other) noexcept {
        value = other.value;
        cout << "Move assignment operator called" << endl;
        return *this;
    }

    // Member function
    void printValue() {
        cout << "Value: " << value << endl;
    }

    // Static member function
    static void staticFunction() {
        cout << "Static function called" << endl;
    }

    // Friend function
    friend void friendFunction(const MyClass& obj);
};

void friendFunction(const MyClass& obj) {
    cout << "Friend function called. Value: " << obj.value << endl;
}

int main()
{
    MyClass obj1;  // Default constructor called
    obj1.value = 10;

    MyClass obj4(20);

    MyClass obj2(obj1);  // Copy constructor called

    MyClass obj3 = std::move(obj4);  // Move constructor called

    obj2 = obj3;  // Copy assignment operator called

    obj3 = std::move(obj2);  // Move assignment operator called

    obj3.printValue();  // Value: 10

    MyClass::staticFunction();  // Static function called

    friendFunction(obj3);  // Friend function called. Value: 10

    return 0；
}