Behavioral Design Patterns in C++ - Basic Implementation - I

This lecture covers the basic implementation of the command design pattern. It starts with an overview of the pattern and proceeds to implement the receiver and invoker classes. The lecture emphasizes avoiding tight coupling between these classes by using a command interface. The implementation is tested, and the class diagram is explained to show how the invoker can execute methods on the receiver without knowing its details, allowing for flexibility and change at runtime.

What is the primary purpose of the command design pattern introduced in the lecture?

• To create a tightly coupled system

• To simplify the user interface

• To separate the request for an action from the object that performs the action

• To enhance the speed of the application

What is the role of the receiver class in the command pattern?

• To execute the command

• To store the command history

• To define the action methods

• To manage user inputs

Why is it important to avoid tight coupling between the invoker and receiver?

• To reduce the number of classes

• To make the invoker dependent on the receiver

• To allow the invoker to work with different receivers

• To increase the complexity of the code

What is the function of the command base class in the command pattern?

• To execute the invoker's methods

• To store the state of the application

• To provide a common interface for all commands

• To manage the application's resources

How does the invoker execute a command without knowing the receiver's details?

• By directly calling the receiver's methods

• By using a pointer to the command interface

• By storing the receiver's state

• By using a global variable

What is the advantage of using the command pattern in terms of runtime flexibility?

• It allows changing the receiver at runtime

• It increases the execution speed

• It reduces memory usage

• It simplifies the code structure

What does the class diagram illustrate about the relationship between invoker and receiver?

• Invoker directly knows the receiver class

• Invoker is tightly coupled with the receiver

• Invoker uses the command interface to interact with the receiver

• Invoker stores the receiver's state