用基类指针调用基类的值构造函数的语法是什么？

#include <iostream>

class Base {
public:
    int value;

    Base(int val) : value(val) {
        std::cout << "Base constructor called." << std::endl;
    }
};

class Derived : public Base {
public:
    Derived(int val) : Base(val) {
        std::cout << "Derived constructor called." << std::endl;
    }
};

int main() {
    Derived derivedObj(10);
    Base* basePtr = &derivedObj;
    basePtr->Base::Base(20); // 通过基类指针调用基类的值构造函数
    std::cout << "Value: " << basePtr->value << std::endl;

    return 0;
}

Base constructor called.
Derived constructor called.
Base constructor called.
Value: 20