对象指针
对象指针定义形式
类名 *对象指针名；
例: Point a(5,10);
Piont *ptr;
ptr=&a;
通过指针访问对象成员（等同于对象名访问对象成员）
对象指针名->成员名
例：ptr->getx() 相当于 (*ptr).getx();
动态创建对象数组
//一维
#include <iostream>
using namespace std;
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; }int getY() const { return y; }void move(int newX, int newY) {x = newX;y = newY;}
private:int x, y;
};
int main(){Point *ptr = new Point[2];//创建对象数组ptr[0].move(5,10);//通过指针访问数组元素的成员ptr[1].move(15,20);cout << "Deleting..." << endl;delete[] ptr;//删除整个对象数组return 0;
}动态创建多维数组
char (*fp)[3];
fp = new char[2][3];
#include <iostream>
using namespace std;
int main() { int (*cp)[9][8] = new int[7][9][8]; for (int i = 0; i < 7; i++) for (int j = 0; j < 9; j++) for (int k = 0; k < 8; k++) *(*(*(cp + i) + j) + k) =（i * 100 + j * 10 + k); for (int i = 0; i < 7; i++) { for (int j = 0; j < 9; j++) { for (int k = 0; k < 8; k++) cout << cp[i][j][k] << " "; cout << endl; } cout << endl; } delete[] cp; return 0;
}将动态数组封装成类
-
更加简洁，便于管理
- 可以在访问数组元素前检查下标是否越界
例 6-18 动态数组类
#include <iostream>
#include <cassert>
using namespace std;
class Point { //类的声明同例6-16 … };
class ArrayOfPoints { //动态数组类
public: ArrayOfPoints(int size) : size(size) { points = new Point[size]; } ~ArrayOfPoints() { cout << "Deleting..." << endl; delete[] points; } Point& element(int index) { assert(index >= 0 && index < size); return points[index]; }
private: Point *points; //指向动态数组首地址 int size; //数组大小
};
int main() { int count; cout << "Please enter the count of points: "; cin >> count; ArrayOfPoints points(count); //创建数组对象 points.element(0).move(5, 0); //访问数组元素的成员 points.element(1).move(15, 20); //访问数组元素的成员 return 0;
}
