《C++語言程式設計基礎》學習之物件複製與移動
阿新 • • 發佈：2018-12-13
淺層複製與深層複製 淺層複製，實現物件間資料元素的一一對應複製。 深層複製，當被複制的物件資料成員是指標型別時，不是複製該指標成員本身，而是將指標所指物件進行復制。 物件的淺層複製：傳遞的是指標的值
class Point { public: Point() :x(0), y(0) { cout << "Default Constructor called." << endl; } Point(int x, int y) :x(x), y(y) { cout << "Constructor called." << endl; } ~Point() { cout << "Destructor called." << endl; } int getX()const { return x; }//常函式成員處理常物件 int getY()const { return y; } void move(int newX, int newY) { x = newX; y = newY; } private: int x, y; }; class ArrayOfPoints { //動態陣列類 public: ArrayOfPoints(int size) :size(size) { points = new Point[size]; } ~ArrayOfPoints() { cout << "Deleting..." << endl; } Point& element(int index) { //返回陣列元素的引用 assert(index >= 0 && index < size); return points[index]; } private: Point *points;//指向動態陣列首地址 int size; //陣列大小 }; int main() { int count; cout << "Please enter the count of points："; cin >> count; ArrayOfPoints points(count);//建立陣列物件 //points.element(0)呼叫類函式，返回物件陣列中的元素的引用，訪問陣列元素的成員 points.element(0).move(5, 0); points.element(1).move(15, 20);//訪問陣列元素的成員 ArrayOfPoints pointsArrayt(points);//建立副本指標指向原先的陣列 cout << "Copy of points:" << endl; cout << "Point_0 of array2: " << pointsArrayt.element(0).getX() << ", " << pointsArrayt.element(0).getY() << endl; cout << "Point_1 of array2: " << pointsArrayt.element(1).getX() << ", " << pointsArrayt.element(1).getY() << endl; points.element(0).move(25, 30); points.element(1).move(35, 40); cout << "After the moving of points:" << endl; cout << "Point_0 of array2: " << pointsArrayt.element(0).getX() << ", " << pointsArrayt.element(0).getY() << endl; cout << "Point_1 of array2: " << pointsArrayt.element(1).getX() << ", " << pointsArrayt.element(1).getY() << endl; return 0; }
物件的深層複製： 在類ArrayOfPoints中增加複製建構函式
class Point { public: Point() :x(0), y(0) { cout << "Default Constructor called." << endl; } Point(int x, int y) :x(x), y(y) { cout << "Constructor called." << endl; } ~Point() { cout << "Destructor called." << endl; } int getX()const { return x; }//常函式成員處理常物件 int getY()const { return y; } void move(int newX, int newY) { x = newX; y = newY; } private: int x, y; }; class ArrayOfPoints { //動態陣列類 public: ArrayOfPoints(int size) :size(size) { points = new Point[size]; } ~ArrayOfPoints() { cout << "Deleting..." << endl; } Point& element(int index) { //返回陣列元素的引用 assert(index >= 0 && index < size); return points[index]; } ArrayOfPoints(const ArrayOfPoints& pointsArray); private: Point *points;//指向動態陣列首地址 int size; //陣列大小 }; ArrayOfPoints::ArrayOfPoints(const ArrayOfPoints& v) { //複製建構函式 cout << "Copy function done!"; size = v.size; points = new Point[size]; for (int i = 0; i < size; i++) points[i] = v.points[i]; } int main() { int count; cout << "Please enter the count of points："; cin >> count; ArrayOfPoints points(count);//建立陣列物件 //points.element(0)呼叫類函式，返回物件陣列中的元素的引用，訪問陣列元素的成員 points.element(0).move(5, 0); points.element(1).move(15, 20);//訪問陣列元素的成員 ArrayOfPoints pointsArrayt(points);//建立副本指標指向原先的陣列 cout << "Copy of points:" << endl; cout << "Point_0 of array2: " << pointsArrayt.element(0).getX() << ", " << pointsArrayt.element(0).getY() << endl; cout << "Point_1 of array2: " << pointsArrayt.element(1).getX() << ", " << pointsArrayt.element(1).getY() << endl; points.element(0).move(25, 30); points.element(1).move(35, 40); cout << "After the moving of points:" << endl; cout << "Point_0 of array2: " << pointsArrayt.element(0).getX() << ", " << pointsArrayt.element(0).getY() << endl; cout << "Point_1 of array2: " << pointsArrayt.element(1).getX() << ", " << pointsArrayt.element(1).getY() << endl; return 0; }
