小编Par*_*ita的帖子

假设我有一个基本模板类Array:

template <class T = Point> class Array{
    protected:
        T* m_data;
        int size;
    public:
        Array();    // constructor
        Array(int n);   // constructor
        Array(const Array<T>& s_data);  //Copy Constructor
        // and so on..
}

它有构造函数和析构函数.我还有一个派生模板类NumericArray:

template <class T = int> 
class NumericArray:public Array<T>{

    public:
        NumericArray();
        NumericArray(int n);
        NumericArray(const NumericArray<T>& s_data);

        ~NumericArray();    //destructor

};

因为我需要初始化基类中的私有成员所以我需要在派生构造函数中调用基础构造函数.但是怎么样？我试过了

template <class T>
NumericArray<T>::NumericArray(int n){
    Array<T>(n);  // it will think I create a Array<T> names n
}

template <class T>
NumericArray<T>::NumericArray(int n):Array(n){
    // No field in NumericalArray called Array …

在头文件中:

class Point{
    public:
        Point();    // constructor
        Point(double x, double y);  // constructor
        Point(Point& A);    //Copy Constructor
        ~Point();   // destructor

        // below are the operator declarations. 
        Point operator - () const; // Negate the coordinates.

    private:
        double xCord;
        double yCord;

};

在Cpp实现文件中,相关的构造函数:

Point::Point(double x, double y){   // constructor
    X(x);// void X(double x) is a function to set the xCord 
    Y(y);// so is Y(y)

}

Point Point::operator-() const{ // Negate the coordinates.
    Point temp(-xCord,-yCord);
    return temp;
    // return Point(-xCord,-yCord); // cannot …