在C++中，聚合是一个进程，一个类将另一个类定义为实体引用(一个类作为另一个类的成员)。 这是另一种重用类的方法。 它是一种表示HAS-A关系的关联形式。
C++聚合示例
下面来看看一个聚合的例子，其中Employee类有Address类的引用作为数据成员。 这样，它可以重用Address类的成员。
#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
}
执行上面代码，得到以下结果 -
101 Beijing Renmin Road-15 Haikou UP