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.
college board sudo code
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 = 17
if (age >= 18):
print("you are an adult")
else:
print("you are a minor")
you are 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):
print("bring an umbrella")
else:
print("the weather is clear")
bring an 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
import random
a = random.randint(0,101)
b = random.randint(0,101)
print(a)
print(b)
if (a > b):
print("a is more than b")
if (a == b):
print("a is the same as b")
else:
print("a is less than b")
38
40
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.
#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
# 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(questions) + " questions.")
answer = input("Are you ready to take a test?")
# Question 1: Boolean Basics
# Ask a question about Boolean values and check the response
# Provide feedback based on the correctness of the response
# Question 2: Boolean Expressions
# Ask a question about Boolean expressions and their importance in programming
# Provide feedback based on the correctness of the response
# Question 3: Conditional Statements
# Ask a question about the purpose of conditional (if-else) statements in programming
# Provide feedback based on the correctness of the response
# Question 4: Relational Operators
# Ask a question about common relational operators in programming and provide examples
# Provide feedback based on the correctness of the response
# Question 5: Logical Operators
# Ask a question about the use of logical operators in programming and provide examples
# Provide feedback based on the correctness of the response
question1 = "what is a boolean value?"
input1 = input(question1)
answer1 = "true or false"
print(question1 + " " + input1)
if (input1 == answer1):
print("correct!")
correct += 1
else:
print("study more! the answer is: " + answer1)
question2 = "what is the product of a boolean expression?"
input2 = input(question2)
answer2 = "boolean value"
print(question2 + " " + input2)
if (input2 == answer2):
print("correct!")
correct += 1
else:
print("study more! the answer is: " + answer2)
question3 = "what is the purpose of conditional statements?"
input3 = input(question3)
answer3 = "to execute statements based on boolean value"
print(question3 + " " + input3)
if (input3 == answer3):
print("correct!")
correct += 1
else:
print("study more! the answer is: " + answer3)
question4 = "what is the purpose of a relational operator and give an example?"
input4 = input(question4)
answer4 = "to test the relationship between variables, expressions, or values; =="
print(question4 + " " + input4)
if (input4 == answer4):
print("correct!")
correct += 1
else:
print("study more! the answer is: " + answer4)
question5 = "what does a logical operator do and give an example?"
input5 = input(question5)
answer5 = "to evaluate multiple conditions to produce a boolean value; and"
print(question5 + " " + input5)
if (input5 == answer5):
print("correct!")
correct += 1
else:
print("study more! the answer is: " + answer5)
# Display the final score
# Calculate the percentage of correct answers and provide feedback
print(user_name + ", you scored " + str(correct) + "/" + str(questions))
Hello, isabelle running /bin/python
You will be asked 5 questions.
what is a boolean value? true or false
correct!
what is the product of a boolean expression? boolean value
correct!
what is the purpose of conditional statements? to execute statements based on boolean value
correct!
what is the purpose of a relational operator and give an example? to test the relationship between variables, expressions, or values; ==
correct!
what does a logical operator do and give an example? to evaluate multiple conditions to produce a boolean value; and
correct!
isabelle, you scored 5/5