Pass the Python Institute PCPP1 PCPP-32-101 Questions and answers with ExamsMirror

The given code snippet demonstrates the concept of encapsulation in object-oriented programming. Encapsulation refers to the practice of keeping the internal state and behavior of an object hidden from the outside world and providing a public interface for interacting with the object. In the given code snippet, the __init__ and get_balance methods provide a public interface for interacting with instances of the BankAccount class, while the __balance attribute is kept hidden from the outside world by using a double underscore prefix.

The @property decorator should be defined after the method that is responsible for setting an encapsulated attribute is a false sentence. In fact, the @property decorator should be defined before the method that is used to set the attribute value. The @property decorator and the setter and deleter methods work together to create an encapsulated attribute, which is used to provide control over the attribute's value.

A socket object is usually created using the socket() constructor provided by the socket module in Python. The correct invocation is socket.socket(socket_domain, socket_type). This creates a new socket object with the specified socket domain and type.

If purple can be obtained from mixing red and blue, which color codes represent the two ingredients? Select two answers)

A. #FFFFFF

B. #0000FF

C. #FF0000

D. #000000

A. In the context of TCP/IP networks, the communication side that initiates a connection is called the client, whereas the side that answers the client is called the server.

This statement is true because TCP/IP networks use a client-server model to establish connection-oriented communications. The client is the device or application that requests a service or resource from another device or application, which is called the server. The server responds to the client’s request and provides the service or resource.For example, when you browse a website using a web browser, the browser acts as a client and sends a request to the web server that hosts the website. The web server acts as a server and sends back the requested web page to the browser1.

B. Connectionless communications are usually built on top of TCP.

This statement is false because TCP (Transmission Control Protocol) is a connection-oriented protocol that requires establishing and terminating a connection before and after sending data. Connectionless communications are usually built on top of UDP (User Datagram Protocol), which is a connectionless protocol that does not require any connection setup or teardown. UDP simply sends data packets to the destination without checking if they are received or not2.

C. Using walkie-talkies is an example of a connection-oriented communication.

This statement is false because using walkie-talkies is an example of a connectionless communication. Walkie-talkies do not establish a dedicated channel or connection between the sender and receiver before transmitting data. They simply broadcast data over a shared frequency without ensuring that the receiver is ready or available to receive it. The sender does not know if the receiver has received the data or not3.

D. A phone call is an example of a connection-oriented communication.

This statement is true because a phone call is an example of a connection-oriented communication. A phone call requires setting up a circuit or connection between the caller and callee before exchanging voice data. The caller and callee can hear each other’s voice and know if they are connected or not. The phone call also requires terminating the connection when the conversation is over4.

References:

1: https://www.techtarget.com/searchnetworking/definition/client-server  2: https://www.javatpoint.com/connection-oriented-vs-connectionless-service  3: https://en.wikipedia.org/wiki/Walkie-talkie  4: https://en.wikipedia.org/wiki/Telephone_call

A is true because in the context of TCP/IP networks, the communication side that initiates a connection is called the client, and the side that answers the client is called the server. This is the basis for establishing a connection-oriented communication.

D is true because a phone call is an example of a connection-oriented communication. Like TCP/IP, a phone call establishes a connection between two devices (in this case, two phones) before communication can occur.

A is true because in the context of TCP/IP networks, the communication side that initiates a connection is called the client, and the side that answers the client is called the server. This is the basis for establishing a connection-oriented communication.

D is true because a phone call is an example of a connection-oriented communication. Like TCP/IP, a phone call establishes a connection between two devices (in this case, two phones) before communication can occur.

B is false because connectionless communications are usually built on top of UDP, not TCP. UDP is a connectionless protocol that does not establish a connection before sending data.

C is false because using walkie-talkies is an example of a connectionless communication. Walkie-talkies do not establish a connection before communication begins, and messages are simply broadcasted to all devices within range.

Here is a sample code in Python using the socket module to create a TCP server and client to demonstrate the connection-oriented communication:

Server-side code:

importsocket

HOST ='127.0.0.1'

PORT =8080

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:

s.bind((HOST, PORT))

s.listen()

conn, addr = s.accept()

with conn:

print('Connected by', addr)

whileTrue:

data = conn.recv(1024)

ifnotdata:

break

conn.sendall(data)

Client-side code:

importsocket

HOST ='127.0.0.1'

PORT =8080

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:

s.connect((HOST, PORT))

s.sendall(b'Hello, world')

data = s.recv(1024)

print('Received',repr(data))

The server listens for incoming connections on port 8080, and when a connection is established, it prints the address of the client that has connected. The server then continuously receives data from the client and sends it back to the client until the connection is closed.

The client establishes a connection with the server and sends the message "Hello, world" encoded as bytes. It then waits for a response from the server and prints the data it receives.

ElementTree is a Python built-in module that provides a simple and efficient API for parsing and creating XML data. It allows you to access and manipulate XML data in a very straightforward way, making it easy to write XML processing applications.

Answer: A. Deserialization is the process of converting data that has been serialized or encoded in a specific format, back into its original form as an object or a data structure in memory. In Python, this typically involves creating Python objects based on sequences of bytes that have been serialized using a protocol such as JSON, Pickle, or YAML.

For example, if you have a Python object my_obj and you want to serialize it to a JSON string, you might do something like this:

importjson

serialized_obj = json.dumps(my_obj)

To deserialize the JSON string back into a Python object, you would use the json.loads() method:

deserialized_obj = json.loads(serialized_obj)

This would convert the JSON string back into its original Python object form.

The correct answer is D. The code is responsible for the support of the inequality operator i.e. i != j. In the given code snippet, the __ne__ method is a special method that overrides the behavior of the inequality operator != for instances of the MyClass class. When the inequality operator is used to compare two instances of MyClass, the __ne__ method is called to determine whether the two instances are unequal.

The correct answer is B. The getNumberofCrosswords() method should be decorated with @classmethod. In the given code snippet, the getNumberofCrosswords method is intended to be a class method that returns the value of the numberofcrosswords class variable. However, the method is not decorated with the @classmethod decorator and does not take a cls parameter representing the class itself. To make getNumberofCrosswords a proper class method, it should be decorated with @classmethod and take a cls parameter as its first argument.

B. The getNumberofCrosswords() method should be decorated with @classmethod.

This is because the getNumberofCrosswords() method is intended to access the class-level variable numberofcrosswords, but it is defined as an instance method, which requires an instance of the class to be created before it can be called. To make it work as a class-level method, you can define it as a class method by adding the @classmethod decorator to the function.

Here's an example of how to define getNumberofCrosswords() as a class method:

classCrossword:

numberofcrosswords =0

def __init__(self, author, title):

self.author = author

self.title = title

Crossword.numberofcrosswords +=1

@classmethod

defgetNumberofCrosswords(cls):

returncls.numberofcrosswords

In this example, getNumberofCrosswords() is defined as a class method using the @classmethod decorator, and the cls parameter is used to access the class-level variable numberofcrosswords.

The cget() method in Python is used to read the configuration options of a widget in Tkinter. It retrieves the value of a specified configuration option for a Tkinter widget. Hence, option A is the correct answer.