C++模板参数继承

// 父类模板
template <typename T, typename U>
class Base {
public:
    void print(T t, U u) {
        std::cout << "T: "<< t << ", U: "<< u << std::endl;
    }
};

// 子类模板，继承父类模板的模板参数
template <typename T, typename U>
class Derived : public Base<T, U> {
public:
    void printDerived(T t) {
        std::cout << "Derived T: "<< t << std::endl;
        // 使用父类模板的print方法
        this->print(t, U());
    }
};

int main() {
    Derived<int, std::string> d;
    d.printDerived(42);
    return 0;
}

// 错误示例
template <typename T>
class Derived : public Base<T, int> { // 错误：父类模板需要两个模板参数
public:
    void printDerived(T t) {
        this->print(t, 42);
    }
};

// 正确示例
template <typename T, typename U>
class Derived : public Base<T, U> { // 正确：继承父类模板的两个模板参数
public:
    void printDerived(T t) {
        this->print(t, U());
    }
};