Boolean

  • A Boolean value is either true or false.
  • A Boolean expression produces a Boolean value (true or false) when evaluated.

Conditional ("if") statements

  • Affect the sequential flow of control by executing different statements based on the value of a Boolean expression.
IF (condition)
{
	<block of statements>
}

The code in <block of statements> is executed if the Boolean expression condition evaluates to true; no action is taken if condition evaluates to false.

IF (condition)
{
	<block of statements>
}
ELSE
{
	<second block of statements>
}

The code in the first <block of statements> is executed if the Boolean expression condition evaluates to true; otherwise, the code in <second block of statements> is executed.

Example: Calculate the sum of 2 numbers. If the sum is greater than 10, display 10; otherwise, display the sum.

num1 = INPUT
num2 = INPUT
sum = num1 + num2
IF (sum > 10)
{
	DISPLAY (10)
}
ELSE
{
	DISPLAY (sum)
}

Hack 1

  • Add a variable that represents an age.

  • Add an ‘if’ and ‘print’ function that says “You are an adult” if your age is greater than or equal to 18.

  • Make a function that prints “You are a minor” with the else function.

## YOUR CODE HERE
age = int(input("Enter your age"))
if age>=18:
    print("You are an adult")
else:
    print("You are a minor")

You are an adult

Relational operators:

  • Used to test the relationship between 2 variables, expressions, or values. These relational operators are used for comparisons and they evaluate to a Boolean value (true or false).

Ex. a == b evaluates to true if a and b are equal, otherwise evaluates to false

  • a == b (equals)
  • a != b (not equal to)
  • a > b (greater than)
  • a < b (less than)
  • a >= b (greater than or equal to)
  • a <= b (less than or equal to)

Example: The legal age to work in California is 14 years old. How would we write a Boolean expression to check if someone is at least 14 years old?

age >= 14

Example: Write a Boolean expression to check if the average of height1, height2, and height3 is at least 65 inches.

(height1 + height2 + height3) / 3 >= 65

Hack 2

  • Make a variable called ‘is_raining’ and set it to ‘True”.

  • Make an if statement that prints “Bring an umbrella!” if it is true

  • Make an else statement that says “The weather is clear”.

## YOUR CODE HERE
is_raining = True
if is_raining ==True:
    print("Bring and umbrella!")
else:
    print("The weather is clear")

Bring and umbrella!

Logical operators:

Used to evaluate multiple conditions to produce a single Boolean value.

  • NOT evaluates to true if condition is false, otherwise evaluates to false
  • AND evaluates to true if both conditions are true, otherwise evaluates to false
  • OR evaluates to true if either condition is true or if both conditions are true, otherwise evaluates to false

Example: You win the game if you score at least 10 points and have 5 lives left or if you score at least 50 points and have more than 0 lives left. Write the Boolean expression for this scenario.

(score >= 10 AND lives == 5) OR (score == 50 AND lives > 0)

Relational and logical operators:

Example: These expressions are all different but will produce the same result.

  • age >= 16
  • age > 16 OR age == 16
  • NOT age < 16

Hack 3

  • Make a function to randomize numbers between 0 and 100 to be assigned to variables a and b using random.randint

  • Print the values of the variables

  • Print the relationship of the variables; a is more than, same as, or less than b

## YOUR CODE HERE
from random import randint
a = randint(1,100)
b = randint(1, 100)
print(a)
print(b)
if(a>b):
    print("a is more than b");
elif(a==b):
    print("a is the same as b")
elif(a<b):
    print("a is less than b")

66
67
a is less than b

Homework

Criteria for above 90%:

  • Add more questions relating to Boolean rather than only one per topic (ideas: expand on conditional statements, relational/logical operators)
  • Add a way to organize the user scores (possibly some kind of leaderboard, keep track of high score vs. current score, etc. Get creative!)
  • Remember to test your code to make sure it functions correctly.
# Import necessary modules
import sys  # Module to access system-related information

# Function to ask a question and get a response
def question_with_response(prompt, answer):
    # Print the question
    print("Question: " + prompt)
    # Get user input as the response
    msg = input()
    if msg.lower() == answer.lower():
        return True
    return False

# Define questions and answers
questions = [
    # Question 1: Boolean Basics
    ("What is the result of True AND False?", "False"),
    # Question 2: Boolean Expressions
    ("What will be the output of (True OR False) AND True?", "True"),
    # Question 3: Conditional Statements
    ("What is the purpose of an if-else statement?", "Control program flow based on conditions"),
    # Question 4: Relational Operators
    ("Provide an example of a relational operator.", "Greater than (>)"),
    # Question 5: Logical Operators
    ("How is the result of NOT True?", "False")
]

# Personalized greeting message
# Collect the student's name
user_name = input("Enter your name: ")
print('Hello, ' + user_name + " running " + sys.executable)
print("You will be asked " + str(len(questions)) + " questions.")
answer = input("Are you ready to take a test? (yes/no) ")

if answer.lower() != "yes":
    print("Okay, goodbye!")
    sys.exit()

# Initialize the correct answers counter
correct = 0

# Ask questions and calculate the score
for prompt, answer in questions:
    if question_with_response(prompt, answer):
        print("Correct!")
        correct += 1
    else:
        print("Incorrect!")

# Display the final score
total_questions = len(questions)
percentage_correct = (correct / total_questions) * 100
print(user_name + ", you scored " + str(correct) + "/" + str(total_questions) + " (" + str(percentage_correct) + "%)")

# Organize and display leaderboard (dummy data for illustration)
leaderboard = {
    "Alice": 4,
    "Bob": 5,
    "Charlie": 3,
    "David": 2,
    user_name: correct
}

sorted_leaderboard = sorted(leaderboard.items(), key=lambda x: x[1], reverse=True)
print("\nLeaderboard:")
for idx, (name, score) in enumerate(sorted_leaderboard):
    print(f"{idx + 1}. {name}: {score}/{total_questions}")

Hello, Sai running /Users/saitalisetty/vscode/student/.conda/bin/python
You will be asked 5 questions.
Question: What is the result of True AND False?
Incorrect!
Question: What will be the output of (True OR False) AND True?
Correct!
Question: What is the purpose of an if-else statement?
Incorrect!
Question: Provide an example of a relational operator.
Correct!
Question: How is the result of NOT True?
Correct!
Sai, you scored 3/5 (60.0%)

Leaderboard:
1. Bob: 5/5
2. Alice: 4/5
3. Charlie: 3/5
4. Sai: 3/5
5. David: 2/5