c++ 多態

1、重載和多態的關係：

多態分爲靜態多態和動態多態：

靜態多態 包含 重載和泛型編程

動態多態 ---》虛函數

 

2、重載案例：

//
// Created by luzhongshan on 10/18/19.
//
#include "stdlib.h"
#include "iostream"
using namespace std;
int Add(int left, int right)
{
    return left + right;
}
double Add(double left, int right)
{
    cout<<"sizeof a: "<< sizeof(left)<<"sizeof b:"<< sizeof(right)<<endl;
    return left + right;
}

int main()
{
    int  a=Add(10, 20);
    cout<<"a  "<<a<<endl;

    //Add(10.0, 20.0);  //這是一個問題代碼
    double b =Add(10.0,20);  //正常代碼
    cout<<"sizeof  b"<< sizeof(b)<<"b  "<<b<<endl;

    return 0;
}

 

3、虛函數案例：

//
// Created by luzhongshan on 10/18/19.
//
#include "iostream"
using namespace std;

class TakeBus
{
public:
    void TakeBusToSubway()
    {
        cout << "go to Subway--->please take bus of 318" << endl;
    }
    void TakeBusToStation()
    {
        cout << "go to Station--->pelase Take Bus of 306 or 915" << endl;
    }
};
//知道了去哪要做什麼車可不行，我們還得知道有沒有這個車
class Bus
{
public:
    virtual void TakeBusToSomewhere(TakeBus& tb) = 0;  //？？？爲什麼要等於0
};

class Subway:public Bus
{
public:
    virtual void TakeBusToSomewhere(TakeBus& tb)
    {
        tb.TakeBusToSubway();
    }
};
class Station :public Bus
{
public:
    virtual void TakeBusToSomewhere(TakeBus& tb)
    {
        tb.TakeBusToStation();
    }
};

int main()
{
    TakeBus tb;
    Bus* b = NULL;
    Bus* a = NULL;
    //假設有十輛公交車，如果是奇數就是去地鐵口的，反之就是去火車站的
    b = new Subway;
    a = new Station;

    b->TakeBusToSomewhere(tb);
    a->TakeBusToSomewhere(tb);
    delete b;
    return 0;
}