Composition
Under Composition, if the parent object is deleted, then the child object also loses its status. Composition is a special type of Aggregation and gives a part-of relationship.
For example, A Car has an engine. If the car is destroyed, the engine is destroyed as well.
public class Engine {
. . .
}
public class Car {
Engine eng = new Engine();
.......
}Aggregation
Aggregation is a directional relation between objects in C#. It is the relationship between objects.
For example, Employee and Address
An Employee is associated with a single Department, whereas a Department can have more than one employee. Let us see an example of Employee and Address.
Example
public class Address {
. . .
}
public class Employee {
private Address addr;
public Employee (Address addr) {
this.addr = addr;
}
. . .
}