Functions (reusable code blocks) in Intro to Computing - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ trace

intermediate

Trace the output of a function call

What is the output of the following code when greet('Anna') is called?

Intro to Computing

def greet(name):
    message = f"Hello, {name}!"
    return message

print(greet('Anna'))

A Hello, Anna!

B Error: name not defined

C greet('Anna')

D Hello, name!

💡 Hint

Look at how the function uses the input name inside the message.

The function greet takes the input name and inserts it into the message string using an f-string. So calling greet('Anna') returns "Hello, Anna!" which is printed.

🧠 Conceptual

intermediate

Understanding function parameters and arguments

Which statement best describes the difference between a function parameter and an argument?

A A parameter is a variable in the function definition; an argument is the actual value passed when calling the function.

B A parameter is the value passed to a function; an argument is the function's output.

C A parameter and an argument are the same thing and can be used interchangeably.

D A parameter is the function's output; an argument is the function's name.

💡 Hint

Think about the function definition versus the function call.

Parameters are placeholders in the function definition that receive values. Arguments are the actual values given to the function when it is called.

❓ Comparison

advanced

Compare two function definitions

Which function definition correctly calculates the square of a number and returns it?

Intro to Computing

Option A:
def square(x):
    return x * x

Option B:
def square(x):
    print(x * x)

Option C:
def square(x):
    return x + x

Option D:
def square(x):
    return x ** 3

A Option B

B Option D

C Option A

D Option C

💡 Hint

Remember that the square of a number is the number multiplied by itself.

Option C returns the product of x times x, which is the square. Option C prints but does not return, so it cannot be used to get the value. Option C adds x to x, which is double, not square. Option C cubes the number.

❓ identification

advanced

Identify the error in the function

What error will occur when running this code?

Intro to Computing

def add_numbers(a, b):
    return a + b

result = add_numbers(5)
print(result)

A SyntaxError: invalid syntax

B TypeError: missing 1 required positional argument: 'b'

C NameError: name 'result' is not defined

D No error, output is 5

💡 Hint

Check how many arguments the function expects versus how many are given.

The function add_numbers requires two arguments, but only one (5) is provided. This causes a TypeError for missing an argument.

🚀 Application

expert

Predict the output of nested function calls

What is the output of this code?

Intro to Computing

def multiply(x, y):
    return x * y

def add_and_multiply(a, b, c):
    return multiply(a + b, c)

result = add_and_multiply(2, 3, 4)
print(result)

A 24

B 14

C Error: multiply function not defined

D 20

💡 Hint

First add a and b, then multiply the sum by c.

The function add_and_multiply adds 2 + 3 = 5, then calls multiply(5, 4) which returns 20.