对象数组

对象数组的定义与访问

  • 定义对象数组

类名 数组名[元素个数]；

  • 访问对象数组元素

通过下标访问
数组名[下标].成员名

对象数组初始化

  • 数组中每一个元素对象被创建时，系统都会调用类构造函数初始化该对象。
  • 通过初始化列表赋值。

例：Point a[2]={Point(1,2),Point(3,4)};

  • 如果没有为数组元素指定显式初始值，数组元素便使用默认值初始化（调用默认构造函数）。
  • 声明一个数组对象，有两种方法

方法1：

  1.     Employee emp[5]={
  2.         Employee("Zhang San", "Haidian", "Beijing"),
  3.         Employee("Li Si", "Xuanwu", "Beijing"),
  4.         Employee("Wang Wu", "Nanfu", "Shanghai"),
  5.         Employee("Zhu Ge", "Wuhou", "Chengdu"),
  6.         Employee("Sun ying", "Zhifu", "Yantai")};

方法2（动态申请内存，类似C#和Java那种写法）

  1.         Employee  *emp1st = new Employee("Li Si", "Xuanwu", "Beijing");//定义一个指针变量emp1st
  2.         emp[0] = *emp1st;//指针所指的对象返回给数组
  3.         delete emp1st;//释放内存


数组元素所属类的构造函数

  • 元素所属的类不声明构造函数，则采用默认构造函数。
  • 各元素对象的初值要求为相同的值时，可以声明具有默认形参值的构造函数。
  • 各元素对象的初值要求为不同的值时，需要声明带形参的构造函数。
  • 当数组中每一个对象被删除时，系统都要调用一次析构函数。

实例代码

  1. #include <iostream>
  2. #include <string>
  3. using namespace std;
  5. int Client::ClientNum = 0;
  6. char Client::ServerName = 'a';
  7. class Employee {
  8. private:
  9.     string name;
  10.     string streeName;
  11.     string city;
  12. public:
  13.     Employee(string n, string s, string c) {
  14.         name = n;
  15.         streeName = s;
  16.         city = c;
  17.     };
  18.     Employee(){
  19.         name ="";
  20.         streeName ="";
  21.         city ="";
  22.     };
  23.     void display();
  24.     string chane_name(string n);
  25. };
  26. void Employee::display(){
  27.     cout << name << streeName << city<<endl;
  28. }
  29. string Employee::chane_name(string n) {
  30.     name = n;
  31.     return name;
  32. }
  33. int main()
  34. {
  35.     //方法1
  36.     Employee emp[5]={
  37.         Employee("Zhang San", "Haidian", "Beijing"),
  38.         Employee("Li Si", "Xuanwu", "Beijing"),
  39.         Employee("Wang Wu", "Nanfu", "Shanghai"),
  40.         Employee("Zhu Ge", "Wuhou", "Chengdu"),
  41.         Employee("Sun ying", "Zhifu", "Yantai")};
  42.     //方法2
  43.     /*Employee emp[5], * empOne = 0;
  44.     empOne = new Employee("Zhang San", "Haidian", "Beijing", "100084");
  45.     emp[0] = *empOne;
  46.     delete empOne;
  47.     empOne = new Employee("Li Si", "Xuanwu", "Beijing", "100031");
  48.     emp[1] = *empOne;
  49.     empOne = new Employee("Wang Wu", "Nanfu", "Shanghai", "012345");
  50.     emp[2] = *empOne;
  51.     empOne = new Employee("Zhu Ge", "Wuhou", "Chengdu", "543210");
  52.     emp[3] = *empOne;
  53.     empOne = new Employee("Sun ying", "Zhifu", "Yantai", "264000");
  54.     emp[4] = *empOne;
  55. */
  56.     for (int i = 0; i < 5; i++) {
  57.         cout << "Number" << i << ':' << endl;
  58.         emp[i].display();
  59.         cout << endl;
  60.     }
  61.     getchar();
  62.     // emp[0].display();
  63.     return 0;
  64. }