Method declaration with def in Ruby - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a method named greet.

Ruby

def [1]
  puts "Hello!"
end

Drag options to blanks, or click blank then click option'

Ahello

Bsay_hello

Cgreet

Dgreeting

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different method name than 'greet'.

Forgetting to write the method name after 'def'.

The method name should be greet as specified.

2fill in blank

medium

Complete the code to declare a method named add that takes two parameters.

Ruby

def [1](a, b)
  a + b
end

Drag options to blanks, or click blank then click option'

Aadd

Bsum

Cplus

Dcombine

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different method name than 'add'.

Leaving out the parameters.

The method name should be add as specified.

3fill in blank

hard

Fix the error in the method declaration by completing the method name.

Ruby

def [1](name)
  puts "Hello, #{name}!"
end

Drag options to blanks, or click blank then click option'

Ahello

Bgreeting

CsayHello

Dgreet

Attempts:

3 left

💡 Hint

Common Mistakes

Using camelCase instead of snake_case.

Choosing a method name that does not match the greeting.

The method name should be greet to match the usage.

4fill in blank

hard

Fill both blanks to declare a method that returns the square of a number.

Ruby

def [1](num)
  num [2] 2
end

Drag options to blanks, or click blank then click option'

Asquare

B*

C**

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using multiplication (*) instead of exponentiation (**).

Choosing a method name that does not describe squaring.

The method name is square and the exponent operator is ** in Ruby.

5fill in blank

hard

Fill all three blanks to declare a method that greets a person with their name and age.

Ruby

def [1](name, age)
  puts "Hello, [2]! You are [3] years old."
end

Drag options to blanks, or click blank then click option'

Agreet_person

B#{name}

C#{age}

Dgreet

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to use string interpolation syntax.

Using a method name that is too generic.

The method name is greet_person. Use Ruby string interpolation #{name} and #{age} to insert values.

Practice

1. What keyword do you use in Ruby to start defining a method?

easy

A. method

B. function

C. define

D. def

Solution

1. Step 1: Understand Ruby method syntax

   In Ruby, methods start with the keyword def and end with end.

2. Step 2: Identify the correct keyword

   The correct keyword to start a method is def, not function, method, or define.

3. Final Answer:

   def -> Option D

4. Quick Check:

   Method start keyword = def [OK]

Hint: Remember: Ruby methods start with 'def' and end with 'end' [OK]

Common Mistakes:

• Using 'function' like in JavaScript
• Using 'method' keyword which doesn't exist
• Forgetting to use 'def' to start method

2. Which of the following is the correct way to declare a method named greet in Ruby?

easy

A. def greet puts "Hello"

B. function greet() { puts "Hello" }

C. def greet() puts "Hello" end

D. method greet() puts "Hello" end

Solution

1. Step 1: Check Ruby method syntax

   Ruby methods start with def method_name() and end with end. Parentheses are optional but allowed.

2. Step 2: Identify correct syntax

   def greet() puts "Hello" end uses def greet() puts "Hello" end, which is correct Ruby syntax. Options B and D use wrong keywords, and C misses end.

3. Final Answer:

   def greet() puts "Hello" end -> Option C

4. Quick Check:

   Correct Ruby method syntax = def greet() puts "Hello" end [OK]

Hint: Use 'def name() ... end' to declare methods in Ruby [OK]

Common Mistakes:

• Forgetting the 'end' keyword
• Using JavaScript style 'function' keyword
• Missing parentheses or using wrong keywords

3. What will be the output of this Ruby code?

def add(a, b)
  a + b
end

puts add(3, 4)

medium

A. 7

B. 34

C. a + b

D. Error

Solution

1. Step 1: Understand method parameters and return

   The method add takes two parameters a and b and returns their sum a + b.

2. Step 2: Calculate the method call result

   Calling add(3, 4) returns 3 + 4 = 7, which is printed by puts.

3. Final Answer:

   7 -> Option A

4. Quick Check:

   3 + 4 = 7 [OK]

Hint: Method returns last expression value; 3 + 4 = 7 [OK]

Common Mistakes:

• Thinking it concatenates as strings
• Expecting explicit return keyword
• Confusing output with code text

4. Identify the error in this Ruby method declaration:

def say_hello
  puts "Hello"

medium

A. Missing 'end' keyword to close method

B. Missing parentheses after method name

C. Incorrect use of puts inside method

D. Method name cannot have underscore

Solution

1. Step 1: Check method structure

   Ruby methods must start with def and end with end. This code misses the end keyword.

2. Step 2: Identify the missing part

   Without end, Ruby will raise a syntax error because the method is not properly closed.

3. Final Answer:

   Missing 'end' keyword to close method -> Option A

4. Quick Check:

   Every method needs 'end' [OK]

Hint: Always close methods with 'end' keyword [OK]

Common Mistakes:

• Forgetting 'end' after method body
• Thinking parentheses are mandatory
• Assuming underscores are invalid in names

5. You want to create a method greet_person that takes a name and returns a greeting like "Hello, Alice!". Which code correctly does this?

hard

A. def greet_person(name)
puts "Hello, #{name}!"
end

B. def greet_person(name)
"Hello, " + name + "!"
end

C. def greet_person(name)
return puts "Hello, " + name + "!"
end

D. def greet_person(name)
print "Hello, " + name + "!"
end

Solution

1. Step 1: Understand method return vs output

   To return a greeting string, the method should produce the string as its last expression or use return. Using puts or print outputs to console but returns nil.

2. Step 2: Analyze each option

   def greet_person(name) "Hello, " + name + "!" end returns the greeting string correctly. def greet_person(name) puts "Hello, #{name}!" end prints but returns nil. def greet_person(name) return puts "Hello, " + name + "!" end returns nil because puts returns nil. def greet_person(name) print "Hello, " + name + "!" end prints but does not return the string.

3. Final Answer:

   def greet_person(name) "Hello, " + name + "!" end -> Option B

4. Quick Check:

   Return string, not print it [OK]

Hint: Return string directly; puts prints but returns nil [OK]

Common Mistakes:

• Using puts instead of returning string
• Returning result of puts (which is nil)
• Confusing print with return