具有抽象函数的 C++ 父类在子类中使用函数

Question

我正在尝试创建一个 C++ 父类，它有两个函数，f1 和 f2，要在子类中实现。这个父类有一个函数abstractedFunction，它抽象了f1 和f2 应该如何一起使用。 f1 和 f2 都在子类中实现，如下代码所示。

#include <iostream>

class Parent
{
public:
    int f1();        // To be implemented in the derived class
    void f2(int i);  // To be implemented in the derived class
    void abstractedFunction() { // Abstracted in the parant class 
        auto r = f1();
        f2(r);
    }
};

class Child : public Parent
{
public:
    int f1() {
        std::cout << "f1 is implemented in the child class\n";
        return 1;
    }

    void f2(int i) {
        std::cout << "f2 is implemented in the child class\n";
        std::cout << "Return value for f1 = " << i << "\n";
    }
};

int main() {
    Child ch;
    ch.abstractedFunction();
    return 0;
}

这样的概念可以在 C++ 中实现吗？

Answer 1

是的，您可以这样做。您需要将基类中定义的函数设为pure virtual : Follow this link to know more about them，然后您可以创建派生类的对象并将其分配给基类指针以进行所需的函数调用

#include <iostream>
using namespace std;

class Parent
{
public:
    virtual int f1()=0;        // To be implemented in the derived class
    virtual void f2(int i)=0;  // To be implemented in the derived class
    void abstractedFunction() { // Abstracted in the parant class 
        auto r = f1();
        f2(r);
    }
};

class Child : public Parent
{
public:
    int f1() {
        std::cout << "f1 is implemented in the child class\n";
        return 1;
    }

    void f2(int i) {
        std::cout << "f2 is implemented in the child class\n";
        std::cout << "Return value for f1 = " << i << "\n";
    }
};

int main() {
    Parent *ptr;
    Child c;
    ptr=&c;
    ptr->abstractedFunction();
    return 0;
}