利用宽高计算三角形和矩形面积，要求用到继承

Rectangular.h

#pragma once

class Rectangular
{
public:
    Rectangular(double width, double height);
    double& showArea();
    void calculateArea();
    Rectangular();
    ~Rectangular();

    double m_s;

private:
    double m_w;
    double m_h;
    
};

Rectangular.cpp

#include "stdafx.h"
#include "Rectangular.h"
#include <iostream>
using namespace std;

void Rectangular::calculateArea(){
    m_s = m_h * m_w;
}

Rectangular::Rectangular(double width, double height){
    m_w = width;
    m_h = height;
}

double& Rectangular::showArea(){
    cout << "多边形面积是：" << m_s << endl;
    return m_s;
}


Rectangular::Rectangular()
{
}


Rectangular::~Rectangular()
{
}

Triangle.h

#pragma once
#include "Rectangular.h"

class Triangle :public Rectangular
{
public:
    Triangle();
    Triangle(double width, double height);

    ~Triangle();
};

Triangle.cpp

#include "stdafx.h"
#include "Triangle.h"

Triangle::Triangle(double width, double height):Rectangular(width,height){

}



Triangle::Triangle()
{
}

Triangle::~Triangle()
{
}

main.cpp

// 继承-23期-92-子羽.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include "Triangle.h"
#include "Rectangular.h"

int _tmain(int argc, _TCHAR* argv[])
{
    Rectangular rec = Rectangular(10, 20);
    rec.calculateArea();
    rec.showArea();

    Triangle tri = Triangle(1,2);
    tri.calculateArea();
    tri.m_s = tri.m_s / 2;
    tri.showArea();
    return 0;
}