Python Institute PCPP-32-101 Exam Questions

The provided code snippet defines a functionf1that accepts variable-length arguments using the*argsand**kwargssyntax. The*argsparameter allows for an arbitrary number of unnamed arguments to be passed to the function as a tuple, while the**kwargsparameter allows for an arbitrary number of named arguments to be passed to the function as a dictionary.

Therefore, the correct statement that best describes the code is:

1. The*argsparameter holds a list of unnamed parameters, while the**kwargsparameter holds a dictionary of named parameters.

Official Python documentation on Function definitions:https://docs.python.org/3/tutorial/controlflow.html#defining-functions

Thearg parameter holds a list of unnamed parameters. In the given code snippet, thef1function takes two arguments:*argand**kwarg. The*argsyntax in the function signature is used to pass a variable number of non-keyword (positional) arguments to the function. Inside the function,argis a tuple containing the positional arguments passed to the function. The**kwargsyntax in the function signature is used to pass a variable number of keyword arguments to the function. Inside the function,kwargis a dictionary containing the keyword arguments passed to the function.

1. 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.

2. 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.

3. 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.

4. 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.

1: https://www.techtarget.com/searchnetworking/definition/client-server2: https://www.javatpoint.com/connection-oriented-vs-connectionless-service3: https://en.wikipedia.org/wiki/Walkie-talkie4: 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 thesocketmodule to create a TCP server and client to demonstrate the connection-oriented communication:

Server-side code:

import socket

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)

while True:

data = conn.recv(1024)

if not data:

break

conn.sendall(data)

Client-side code:

import socket

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.

In Python,typeis the built-in metaclass that serves as the base class for all new-style classes. All new-style classes in Python, including built-in types likeintandstr, are instances of thetypemetaclass and inherit from it.

Option B is true because theunbind()method is invoked from within a widget's object1.

Option D is true because theunbind()method needs the event name as an argument1.

Theunbind()method in Tkinter is used to remove a binding between an event and a function. It can be invoked from within a widget's object when a binding is no longer needed. The method requires the event name as an argument to remove the binding for that specific event. For example:

button = tk.Button(root, text='Click me')

button.bind('<Button-1>', callback_function) # bind left mouse click event to callback_function

button.unbind('<Button-1>') # remove the binding for the left mouse click event