C++动态数组的创建及应用

蔚落 2022-02-24 17:16 194阅读 0赞

/*---------------------------------------
    功能：动态数组的创建和应用
    运行结果：
    Input the number of point: 2
    Calling default constructor of Point...
    Calling default constructor of Point...
    Calling constructor of ArrayPoint...
    (5, 0)
    (15, 12)
    Calling destructor of PointArray...
    Calling destructor of Point...
    Calling destructor of Point...
    -----------------------------------------
    Author: Zhang Kaizhou
    Date: 2019-4-4 17:23:48
    ----------------------------------------*/
    #include <iostream>
    
    using namespace std;
    
    class Point{ // 创建一个点Point类
    private:
        int x, y;
    public:
        Point(){ cout << "Calling default constructor of Point..." << endl; } // 默认构造函数
        Point(int xx, int yy):x(xx), y(yy){ cout << "Calling parameter constructor of Point..." << endl; } // 含参构造函数
        Point(Point & p){ // 复制构造函数
            x = p.x;
            y = p.y;
        }
        ~Point(){ cout << "Calling destructor of Point..." << endl; } // 析构函数
        void showPos(){ cout << "(" << x << ", " << y << ")" << endl; }
        void movePos(int xx, int yy){ x = xx; y = yy; }
    };
    
    class PointArray{ // 创建PointArray类
    private:
        Point * points; // 指向动态数组首地址的指针
        int len; // 数组长度
    public:
        PointArray(int len):len(len){ points = new Point[len]; cout << "Calling constructor of ArrayPoint..." << endl; } // 构造函数，利用new关键字动态创建len长度的数组
        ~PointArray(){ cout << "Calling destructor of PointArray..." << endl; delete [] points; } // 析构函数
        Point & element(int index){ // 该函数的返回值是一个Point类的对象的引用
            if(index >= 0 && index < len){
                return points[index];
            }else{
                cout << "The index is overstep!" << endl;
                exit(0); // 退出系统
            }
        }
    };
    
    int main(){
        int pointCount;
        cout << "Input the number of point: ";
        cin >> pointCount; // 点总数
        PointArray points(pointCount); // 创建一个点数组对象points，点的总数为pointCount
        points.element(0).movePos(5, 0);
        points.element(1).movePos(15, 12);
        points.element(0).showPos();
        points.element(1).showPos();
    
        return 0;
    }