從主 function 調用變量到其他類&無法使用這個？

Question

當所有類都放在一個包含所有類的主 cpp 文件中時，我能夠運行該程序。 但是，當我將 cpp 文件拆分為各自的 header 文件和 cpp 文件時，出現了一些錯誤。

以下是我正在使用的所有文件（它們都在一個文件夾中）：

1) Assignment.cpp  (where the main function is at)
2) ShapeTwoD.cpp (Where the parent class is at)
3) ShapeTwoD.h
3) Square.cpp (Child Class)
4) Square.h
5) Rectangle.cpp (Child class)
6) Rectangle.h

問題一：

我有兩個變量：

ShapeTwoD * Shape2D [100];

int size = 0;
   

以上變量主要在function中。 我嘗試在其他類中調用上述變量，但是有一個錯誤表明它沒有在 scope 中聲明。 我也嘗試添加 extern，但似乎也存在一些錯誤。 我已將變量移至父 class，Shape2D.cpp，但是，主 cpp 無法檢測到變量名稱。 我還公開了：在父 cpp 下。

如果有人可以幫助我，我將非常感激，因為我真的沒時間了。 溫馨問候

Square.h：

Square.cpp：

class Square: public ShapeTwoD{

    public:

    Square(string name, bool containsWarpSpace, vector < pair<int, int> > vect):ShapeTwoD(name,containsWarpSpace,vect,radius){

        this->vect = vect;
        this->name = name;
        this->containsWarpSpace = containsWarpSpace;


    }
    double computeArea();
    bool isPointOnShape(int x, int y);
    bool isPointInShape(int x, int y);
    vector<pair<int,int> >allCoord();
    void setInnerCoord(vector<pair<int,int> > innerCoord);
    vector<pair<int,int> > getInnerCoord();
    void setOuterCoord(vector<pair<int,int> > outerCoord);
    vector<pair<int,int> > getOuterCoord();
    string toString();
    void calculatePerimeter();

    ~Square(){

    }



};

double Square::computeArea(){

        int width;
        int area;

      std::vector< pair<int, int> >::iterator result = std::max_element(this->vect.begin(), this->vect.end());
      int positionMax = std::distance(this->vect.begin(), result);

       pair<int, int> maxCoordinate = this->vect[positionMax];



    for(int i = 0; i < this->vect.size(); i++){
        if(this->vect[i].second == maxCoordinate.second && this->vect[i] != maxCoordinate){
            width = maxCoordinate.first - this->vect[i].first;
            area = width * width;
        }

    }


    return area;
}

bool Square::isPointOnShape(int x, int y){
     bool result = false;

      std::vector< pair<int, int> >::iterator resultMax = std::max_element(this->vect.begin(), this->vect.end());
          int positionMax = std::distance(this->vect.begin(), resultMax);

          std::vector< pair<int, int> >::iterator resultMin = std::min_element(this->vect.begin(), this->vect.end());
          int positionMin = std::distance(this->vect.begin(), resultMin);

           pair<int, int> maxCoordinate = this->vect[positionMax];
           pair<int, int> minCoordinate = this->vect[positionMin];

           for(int i = 0; i < this->vect.size();i++){

               if(maxCoordinate.first == x || maxCoordinate.second == y || minCoordinate.first == x || minCoordinate.second == y){
                   result = true;
               }
               else{
                   result = false;
               }
           }




    return result;
}

ShapeTwoD.cpp（父類）：

class ShapeTwoD{

    protected:
    string name;
    bool containsWarpSpace;
    vector < pair<int, int> > vect;
    int radius;
    double area;
    vector < pair<int, int> > innerCoord;
    vector < pair<int, int> > outerCoord;




    private:


    public:

    ShapeTwoD(){


    }

    ShapeTwoD(string name, bool containsWarpSpace, vector < pair<int, int> > vect, int radius){
        this->radius = radius;
        this->vect = vect;
        this->name = name;
        this->containsWarpSpace = containsWarpSpace;

    }
    virtual double computeArea();
    virtual bool isPointInShape(int x, int y);
    virtual bool isPointOnShape(int x, int y);
    virtual vector<pair<int,int> > allCoord();
    virtual void setInnerCoord(vector<pair<int,int> > innerCord);
    virtual vector<pair<int,int> > getInnerCoord();
    virtual void setOuterCoord(vector<pair<int,int> > outerCoord);
    virtual vector<pair<int,int> > getOuterCoord();
    virtual string toString();
    virtual void calculatePerimeter();

    virtual ~ShapeTwoD(){

    }



    string getName();
    bool getContainsWarpSpace();





    void setName(string name);
    void setContainsWarpSpace(bool containsWarpSpace);


    void setCoord(vector < pair<int, int> > v);
    vector < pair<int, int> > getCoord();
    void setArea(double area);
    double getArea();


};

主功能（）：

int main() {

ShapeTwoD * obj;


int x;
int y;
int radius;

string menu = "0";

while(menu != "5"){
    cout <<"----------------------------------" << endl;
    cout << "1) Input sensor data" <<endl;
    cout << "5) Quit\n" <<endl;
    cout << "Please enter your choice:";
    cin >> menu;




if(menu == "1"){

cout << "[ Input sensor data ]" << endl;

    cout << "Please enter name of shape :";
    cin >> shape;
    transform(shape.begin(), shape.end(), shape.begin(), ::tolower);
    cout << "Please enter special type :";
    cin >> specialtype;
    transform(specialtype.begin(), specialtype.end(), specialtype.begin(), ::tolower);



 if(shape == "rectangle"){
     vector < pair<int, int> > temp;
    for(int i = 0; i < 4; i++){
                cout << "Please enter x-ordinate of pt " << i+1 <<" :";
                cin >> x;
                cout << "Please enter y-ordinate of pt " << i+1 << " :";
                cin >> y;

                  std::pair <int,int> p;
                  p = std::make_pair (x,y);
                  temp.push_back(p);

            }


    obj = new Rectangle(shape,"",temp);


      if(specialtype == "ws"){
          obj->setContainsWarpSpace(true);

 }
      else if (specialtype == "ns"){
          obj->setContainsWarpSpace(false);

      }

      Shape2D[size] = obj;
      size ++;
      temp.clear();



    cout << "\nRecords successfully stored. Going back to main menu ...\n" << endl;


    }
else if(shape == "square" ){

     vector < pair<int, int> > temp;

    for(int i = 0; i < 4; i++){
                cout << "Please enter x-ordinate of pt " << i+1 <<" :";
                cin >> x;
                cout << "Please enter y-ordinate of pt " << i+1 << " :";
                cin >> y;

                  std::pair <int,int> p;
                  p = std::make_pair (x,y);


                temp.push_back(p);


            }

    obj = new Square(shape,"",temp);


      if(specialtype == "ws"){
          obj->setContainsWarpSpace(true);

  }
      else if (specialtype == "ns"){
          obj->setContainsWarpSpace(false);

      }



      temp.clear();
      Shape2D[size] = obj;
      size ++;

    cout << "\nRecords successfully stored. Going back to main menu ...\n" << endl;




}


    cout << "\nRecords successfully stored. Going back to main menu ...\n" << endl;






}

Answer 1

對於問題一，最合乎邏輯的地方是 ShapeTwoD 中的ShapeTwoD成員。 將以下內容放入 shapetwod.h：

class ShapeTwoD {
  public:
    static vector<shared_ptr<ShapeTwoD>> allShapes;
};

並在 shapetwod.cpp 中定義：

vector<shared_ptr<ShapeTwoD>> ShapeTwoD::allShapes;

然后，您可以使用ShapeTwoD::allShapes從其他地方訪問此向量。
注意：從 C++17 開始，您可以放棄額外的定義，並使聲明inline static 。