C++聚合

在C++中，聚合是一個進程，一個類將另一個類定義為實體引用(一個類作為另一個類的成員)。 這是另一種重用類的方法。 它是一種表示HAS-A關係的關聯形式。

C++聚合示例

下麵來看看一個聚合的例子，其中Employee類有Address類的引用作為數據成員。 這樣，它可以重用Address類的成員。

#include <iostream>
using namespace std;
class Address {
    public:
   string addressLine, city, state;
     Address(string addressLine, string city, string state)
    {
        this->addressLine = addressLine;
        this->city = city;
        this->state = state;
    }
};
class Employee
    {
        private:
        Address* address;  //Employee HAS-A Address
        public:
        int id;
        string name;
        Employee(int id, string name, Address* address)
       {
           this->id = id;
           this->name = name;
           this->address = address;
       }
     void display()
       {
           cout<<id <<" "<<name<< " "<<
             address->addressLine<< " "<< address->city<< " "<<address->state<<endl;
       }
   };
int main(void) {
    Address a1= Address("Renmin Road-15","Haikou","UP");
    Employee e1 = Employee(101,"Beijing",&a1);
            e1.display();
   return 0;
}

執行上面代碼，得到以下結果 -

101 Beijing Renmin Road-15 Haikou UP