c++

转载：https://blog.csdn.net/gogogo_sky/article/details/72860426

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简单示例：

重新定义

#include<iostream>
using namespace std;

class a {
public:
    void fun() {
        cout << "a";
    }
};

class b:public a {
public:
    void fun(int s) {
        cout << "b";
    }
};

class c :public a {

};

int main() {
    b* b1 = new b();
    b1->fun(2); //子类中重新实现
    c* c1 = new c();
    c1->fun();//子类中没有重新实现
}

重写

#include<iostream>
using namespace std;

class a {
public:
    virtual void fun() {
        cout << "a"<<endl;
    }
    void fun2() {
        cout << "a no virtual" << endl;
    }
};

class b:public a {
public:
    void fun() {
        cout << "b"<<endl;
    }
};

class c :public a {
    void fun(int cval) {
        cout << "c" << endl;
    }
    void fun2() {
        cout << "c no virtual" << endl;
    }
};

int main() {
    a* b1 = new b();
    b1->fun();//b中重写
    a* c1 = new c();
    c1->fun();//c中无重写
    c1->fun2();
}