c++ - 没有构造函数实例 "Class:Class"匹配参数列表

Question

我试图通过执行以下练习来理解 C++ 中的构造函数和继承:

Write a program that defines a shape class with a constructor that gives value to width and height. The define two sub-classes triangle and rectangle, that calculate the area of the shape area (). In the main, define two variables a triangle and a rectangle and then call the area() function in this two variables.

我尝试编写构造函数:

#include <iostream>
using namespace std;

class Shape
{
protected:
    double width, height;
public:
    // Define constructor
    Shape(double newWidth, double newHeight):
        width{newWidth}, height{newHeight} {}
    // Define getters
    double getWidth() const
    {
        return width;
    }
    double getHeight() const
    {
        return height;
    }
};

class Rectangle: public Shape
{
public:
    double area()
    {
        return (width*height);
    }
};

class Triangle: public Shape
{
public:
    double area()
    {
        return (width*height)/2;
    }
};

int main ()
{
    Rectangle rect(5.0,3.0);
    Triangle tri(2.0,5.0);
    cout << rect.area() << endl;
    cout << tri.area() << endl;
    return 0;
}

给出以下错误:

no instance of constructor "Rectangle::Rectangle" matches the argument list -- argument types are: (double, double)

我认为错误来自于我如何实例化 rect和 tri但我似乎无法解决这个问题。有什么建议？

Answer 1

构造函数不是继承的。如果你想继承构造函数，你可以:

class Rectangle : public Shape
{
public:
  using Shape::Shape;

  // etc.
};