c++ - 覆盖 'virtual void ' C++ 错误

Question

下面的代码给我一个错误。

Error: overriding 'virtual void Animal::getClass()', where it says virtual void getClass() { cout << "I'm an animal" << endl; }

Error: conflicting return type specified for 'virtual int Dog::getClass()', where it says getClass(){ cout << "I'm a dog" << endl; }

另外，它说:

Class 'Dog' has virtual method 'getClass' but non-virtual destructor

#include <iostream>
#include <vector>
#include <string>
#include <fstream>
#include<sstream>
#include <stdlib.h>     // srand, rand
#include <stdio.h>

using namespace std;

class Animal{

public:
    void getFamily(){ cout << "We are animals " << endl;}

    virtual void getClass() { cout << "I'm an animal" << endl; }
};

class Dog : public Animal{

public:
    getClass(){ cout << "I'm a dog" << endl; }

};

void whatClassAreYou(Animal *animal){

    animal -> getClass();

}

int main(){

    Animal *animal = new Animal;
    Dog *dog = new Dog;

    animal->getClass();
    dog->getClass();

    whatClassAreYou(animal);
    whatClassAreYou(dog);


    return 0;
}

Answer 1

将 Dog 类中的定义更改为:

void getClass() { /* ... */ }

当您声明它时没有返回类型，编译器会将返回类型设置为 int。这会产生错误，因为被覆盖的方法必须具有与其覆盖的基类方法相同的返回类型。