Question

Define these classes: Laser, Claw, and SmartPhone. Each has only one method: does(). This returns 'disintegrate' (Laser), 'crush' (claw), or 'ring' (SmartPhone). Then, define the class Robot that has one instance (object) of each of these. Define a does() method for the Robot that prints what its component objects do.

Short answer

Define classes with `does()` methods and integrate them in Robot.

Step-by-step solution

Define the Laser Class

Define a class named `Laser` with a method `does()` that returns the string `"disintegrate"`. In Python, it looks like this: ```python class Laser: def does(self): return "disintegrate" ```

Define the Claw Class

Define a class named `Claw` with a method `does()` that returns the string `"crush"`. In Python, the implementation is: ```python class Claw: def does(self): return "crush" ```

Define the SmartPhone Class

Define a class named `SmartPhone` with a method `does()` that returns the string `"ring"`. In Python, write it like this: ```python class SmartPhone: def does(self): return "ring" ```

Define the Robot Class

Define the `Robot` class, which should contain instances of `Laser`, `Claw`, and `SmartPhone`. Implement the `does()` method to call the `does()` method of each of these instances and print their outputs. ```python class Robot: def __init__(self): self.laser = Laser() self.claw = Claw() self.smartphone = SmartPhone() def does(self): laser_action = self.laser.does() claw_action = self.claw.does() smartphone_action = self.smartphone.does() return f"Laser: {laser_action}, Claw: {claw_action}, SmartPhone: {smartphone_action}" ```

Test the Robot Class

Create an instance of the `Robot` class and call its `does()` method to verify that it collects the actions of its components correctly. ```python robot = Robot() print(robot.does()) # Outputs: Laser: disintegrate, Claw: crush, SmartPhone: ring ```

Key concepts

Object-Oriented Programming

Object-Oriented Programming (OOP) is a programming paradigm centered around objects rather than actions. These objects are instances of classes, which can be thought of as blueprints for creating objects. Each class can have attributes (which describe the object) and methods (which define the object's behaviors).

In OOP, we aim to encapsulate the data and functions within a single unit called a class. This approach helps in organizing and managing code efficiently, making it scalable and easier to maintain.

For example, in the exercise, we are dealing with classes like `Laser`, `Claw`, and `SmartPhone`. Each of these classes represents a distinct blueprint for objects with a specific purpose or action:

• Laser encapsulates the behavior of disintegrating.
• Claw is defined to perform a crushing action.
• SmartPhone is tasked with ringing.

Thus, OOP allows us to create objects based on these classes that behave according to their defined methods.

Method Definition

A method in programming refers to a function that is defined within a class. It operates on the data contained within that class, allowing objects of that class to perform specific actions or behaviors.

When defining a method, you begin with the `def` keyword, followed by the method's name and parentheses, which may include parameters. In Python, every method in a class automatically takes the class instance (often referred to as `self`) as its first argument, allowing the method to access the class's attributes and other methods.

Take, for instance, the `does()` method in each class from the assignment:

• Laser class method does() returns the string `"disintegrate"`.
• Claw class method does() returns the string `"crush"`.
• SmartPhone class method does() provides the action `"ring"`.

Methods like these encapsulate the behavior of the class, ensuring that the object's actions are consistent and predictable.

Class Composition

Class composition is a principle of object-oriented programming where a class is made up of other classes, allowing the encapsulation of complex functionalities. Instead of inheriting behaviors, composition involves including instances of other classes as attributes within a new class, which can then delegate specific functionality to these instances.

In the provided exercise, the `Robot` class demonstrates class composition. It contains instances of the `Laser`, `Claw`, and `SmartPhone` classes:

• The `Robot` class has attributes that store instances of each component class (i.e., self.laser, self.claw, self.smartphone).
• The `does()` method of the `Robot` makes calls to the `does()` method of each constituted object, thereby aggregating their actions.

This composition allows the `Robot` class to utilize functionalities of the `Laser`, `Claw`, and `SmartPhone` classes collaboratively, without having to implement each action itself. It exemplifies the design principle of "composition over inheritance," where class functionality is built by combining simple objects to tackle complex scenarios.