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())
if age>18:
print("You are an adult")
else:
print("You are a a minor")
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==1:
print("bring an umbrella")
else:
print("the weather is clear")
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
import random
x=random.randint(0,100)
x1=random.randint(0,100)
if x==x1:
print("a is the same as b", x, x1)
if x>=x1:
print("a is greater then b", x,">", x1)
if x<=x1:
print("b is greater then a", x,"<", x1)
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.
#HOMEWORK
# The quiz contains questions related to Boolean values, Boolean expressions,
# conditional statements, relational operators, and logical operators.
# Import necessary modules
import getpass # Module to get the user's name
import sys # Module to access system-related information
# Function to ask a question and get a response
def question_with_response(prompt):
# Print the question
print("Question: " + prompt)
# Get user input as the response
msg = input()
return msg
# Define the number of questions and initialize the correct answers counter
questions = 5
correct = 0
user_name=input()
# Question 1: Boolean Basics
response = question_with_response("What are the possible values of a Boolean variable?")
if response.lower() == "true or false":
print("Correct!")
correct += 1
else:
print("Incorrect.")
# Question 2: Boolean Expressions
response = question_with_response("Why are Boolean expressions important in programming?")
if "control flow" in response.lower() and "decision making" in response.lower():
print("Correct!")
correct += 1
else:
print("Incorrect.")
# Question 3: Conditional Statements
response = question_with_response("What is the purpose of conditional (if-else) statements in programming?")
if "execute different code" in response.lower() and "conditions met" in response.lower():
print("Correct!")
correct += 1
else:
print("Incorrect.")
# Question 4: Relational Operators
response = question_with_response("Give an example of a relational operator in programming.")
if response.lower() == "==" or response.lower() == "<=" or response.lower() == ">=":
print("Correct!")
correct += 1
else:
print("Incorrect.")
# Question 5: Logical Operators
response = question_with_response("Provide an example of a logical operator in programming.")
if response.lower() == "and" or response.lower() == "or" or response.lower() == "not":
print("Correct!")
correct += 1
else:
print("Incorrect.")
# Display the final score
percentage_correct = (correct / questions) * 100
print(user_name + ", you scored " + str(correct) + "/" + str(questions) + " which is " + str(percentage_correct) + "%.")
Question: What are the possible values of a Boolean variable?