What is a container class? What are the types of container classes?

1. What is a container class? What are the types of container classes? A container class is a class that is used to hold objects in memory or
   external storage. A container class acts as a generic holder. A
   container class has a predefined behavior and a well-known interface. A
   container class is a supporting class whose purpose is to hide the
   topology used for maintaining the list of objects in memory. When a
   container class contains a group of mixed objects, the container is
   called a heterogeneous container; when the container is holding a group
   of objects that are all the same, the container is called a homogeneous
   container.