Question

以下是我的代码

的问题

我有一个父类Shape和一个子类Square

struct Point
{
    int x,y;
};

class Shape
{
private:
    string name;

public:
    void setName(string);
    string getName();
    virtual void setVerticlePoint() { };
    virtual Point getVerticlePoint();
};

下面是Square.cpp

class Square: public Shape
{
private:
    Point verticlePoint[4];

public:
    int noOfVerticles() const { return 5; }
    void setVerticlePoint();
    Point getVerticlePoint();
};

void Square::setVerticlePoint()
{
    int xData,yData;

    for(int i=0; i<4; i++)
    {
        cout << "Please enter x-ordinate of pt." << i << " :";
        cin > xData;
        cout << "Please enter y-ordinate of pt." << i << " :";
        cin >> yData;
        verticlePoint[i]->x = xData;
        verticlePoint[i]->y = yData;
    }
}

所以在main.cpp，我做了这个

int main()
{
    Shape *point[5];
    Point vertic`lePoint;
    Square *cro = new Square();

    // some codes in between

    // now i prompt for verticle point

    shape[0] = squr;

    //assuming myShape & myType is some string value
    shape[0]->setName(myShape);
    shape[0].setType(myType);

    //here i will be prompt to key in 4 times of X & y Ordinate of the verticle point
    shape[0]->setVerticlePoint();

    //Now the issue is i need to retrieve back my verticle point that i store in shape[0].

    //here no issue
    cout << "Get Name: " << shape[0]->getName() << endl;
    cout << "Get Data:"  << shape[0]->getType() << endl;
    //the top 2 works

    //this is the issue
    verticlePoint = shape[0]->getVerticlePoint();
    cout << sizeof(verticlePoint);
    //it output as size 8 , no matter which shape i use, i got other shapes with different verticle point.

    return 0;
}

问题是：

如何检索verticlePoint[array]（例如，对于square是verticlePoint[4]，如何将Point检索到主类中的变量，然后使用for循环调出{{1} x,y shape[0]到verticlePoint[0]

的verticlePoint[4]

感谢您的帮助！

Answer 1

显然，您希望根据形状返回不同数量的点。为此，您可以使用std::vector<Point>作为返回类型...例如：

class Shape
{
private:
    string name;

public:
    void setName(string);
    string getName();
    virtual void setVerticlePoint() { };
    virtual std::vector<Point> getVerticlePoint();
};

例如，

然后在正方形中，你将返回一个4点的矢量......

std::vector<Point> Square::getVerticlePoint()
{
    return std::vector<Point>(verticlePoint, verticlePoint+4);
}

从子类获取Struct并在主类中使用

1 个答案: