C++ 介面(純虛擬函式)

c++ 介面的實現， 注意繼承的時候要公開繼承 : public Box

#include <iostream>
using namespace std;


class Box
{
public:
    // 純虛擬函式
    virtual double getVolume() = 0;
    double length;      // 長度
    double breadth;     // 寬度
    double height;      // 高度
};

class WhiteBox : public Box {
public:
    virtual double getVolume() override
    {
        return this->length * this->breadth * this->height;
    }
};


void main()
{
    WhiteBox white_box;
    white_box.breadth = 1;
    white_box.length = 2;
    white_box.height = 3;

    cout<< white_box.getVolume() << endl;
    system("pause");
}