在c++的继承类中声明构造函数时出错

class Base {
public:
    Base(int x) { /* ... */ }
};

class Derived : public Base {
public:
    Derived(int x) { /* ... */ } // 错误：未调用Base(int)
};

class Derived : public Base {
public:
    Derived(int x) : Base(x) { /* ... */ } // 正确：显式调用Base(int)
};

class Base {
public:
    Base(int x) { /* ... */ }
};

class Derived : public Base {
public:
    Derived(double x) { /* ... */ } // 错误：参数类型不匹配
};

class Derived : public Base {
public:
    Derived(double x) : Base(static_cast<int>(x)) { /* ... */ } // 正确：类型转换
};

class Base {
public:
    Base() { /* ... */ }
};

class Derived : public Base {
public:
    Derived() { /* ... */ } // 正确，但如果有其他构造函数可能会导致混淆
    Derived(int x) : Base(x) { /* ... */ }
};