Print and println output in Kotlin - Mini Project: Build & Apply

Print and println output

📖 Scenario: You are learning how to show messages on the screen using Kotlin. This is like writing notes on a paper to share with friends.

🎯 Goal: You will write Kotlin code to print messages using print and println functions and see how they behave differently.

📋 What You'll Learn

Create a variable with a message

Use print to show the message without moving to a new line

Use println to show the message and move to a new line

Print multiple messages to observe the difference

💡 Why This Matters

🌍 Real World

Printing messages is the first step to communicate with users in programs, like showing instructions or results.

💼 Career

Understanding how to display output is essential for debugging and user interaction in software development.

1

Create a message variable

Create a variable called message and set it to the text "Hello, Kotlin!"

Kotlin

# Create a variable called message with the text "Hello, Kotlin!"
# Your code here

Hint

Use val to create a variable that does not change.

2

Print the message using print

Use print(message) to show the message without moving to a new line

Kotlin

val message = "Hello, Kotlin!"
# Use print(message) to show the message without a new line
# Your code here

Hint

print shows text but stays on the same line.

3

Print the message using println

Use println(message) to show the message and move to a new line

Kotlin

val message = "Hello, Kotlin!"
print(message)
# Use println(message) to show the message and move to a new line
# Your code here

Hint

println shows text and moves to the next line.

4

Print multiple messages to compare

Print print(message) followed by println(message) and then println("Done") to see how lines change

Kotlin

val message = "Hello, Kotlin!"
print(message)
println(message)
# Print println("Done") to show Done on a new line
# Your code here

Hint

Observe how print and println affect the output lines.

Practice

1. What is the main difference between print and println in Kotlin?

easy

A. print outputs only numbers; println outputs only text.

B. print adds a newline after output; println outputs text without a newline.

C. print outputs text without a newline; println adds a newline after output.

D. print is used for debugging; println is used for user messages.

Solution

1. Step 1: Understand print behavior

   print outputs text exactly as given and stays on the same line.

2. Step 2: Understand println behavior

   println outputs text and then moves the cursor to the next line.

3. Final Answer:

   print outputs text without a newline; println adds a newline after output. -> Option C

4. Quick Check:

   print no newline, println newline = A [OK]

Hint: Remember: println adds a line break, print does not [OK]

Common Mistakes:

• Confusing which function adds a newline
• Thinking print adds a newline
• Assuming println outputs only numbers

2. Which of the following is the correct syntax to print "Hello" and then move to a new line in Kotlin?

easy

A. println("Hello")

B. print("Hello")

C. println Hello

D. println["Hello"]

Solution

1. Step 1: Check syntax correctness

   Only println("Hello") uses correct function call syntax with parentheses and quotes.

2. Step 2: Verify output behavior

   println("Hello") prints "Hello" and moves to a new line automatically.

3. Final Answer:

   println("Hello") -> Option A

4. Quick Check:

   Correct syntax with println = A [OK]

Hint: Use parentheses and quotes exactly for print/println [OK]

Common Mistakes:

• Missing parentheses around arguments
• Using square brackets instead of parentheses
• Omitting quotes around strings

3. What will be the output of the following Kotlin code?

print("Hi")
println(" there")
print("Welcome")

medium

A. Hi there
Welcome

B. Hi
there
Welcome

C. Hi there Welcome

D. Hi there
Welcome

Solution

1. Step 1: Trace first print statement

   print("Hi") outputs "Hi" without newline.

2. Step 2: Trace println statement

   println(" there") outputs " there" and moves to next line.

3. Step 3: Trace last print statement

   print("Welcome") outputs "Welcome" on the new line.

4. Final Answer:

   Hi there Welcome -> Option D

5. Quick Check:

   print no newline, println newline = D [OK]

Hint: Remember print stays on line; println moves to next line [OK]

Common Mistakes:

• Assuming print adds newline
• Ignoring space in " there"
• Thinking all output is on one line

4. Identify the error in this Kotlin code snippet:

print("Hello")
println "World"

medium

A. Missing parentheses in println call

B. Missing quotes around Hello

C. print cannot be used without println

D. No error, code runs fine

Solution

1. Step 1: Check syntax of print statement

   print("Hello") is correct with parentheses and quotes.

2. Step 2: Check syntax of println statement

   println "World" is missing parentheses around the argument, which is required in Kotlin.

3. Final Answer:

   Missing parentheses in println call -> Option A

4. Quick Check:

   Function calls need parentheses = B [OK]

Hint: Always use parentheses for function calls in Kotlin [OK]

Common Mistakes:

• Omitting parentheses in function calls
• Thinking print needs println to work
• Confusing quotes usage

5. You want to print the numbers 1, 2, and 3 on the same line separated by spaces, then print "Done" on the next line. Which Kotlin code achieves this?

hard

A. print("1 2 3")
print("Done")

B. print("1 2 3")
println("Done")

C. print("1 ")
print("2 ")
print("3\n")
println("Done")

D. println("1")
println("2")
println("3")
print("Done")

Solution

1. Step 1: Print numbers on same line with spaces

   Using print("1 2 3") outputs "1 2 3" on the same line.

2. Step 2: Print "Done" on next line

   println("Done") prints "Done" and moves to the next line.

3. Final Answer:

   print("1 2 3") println("Done") -> Option B

4. Quick Check:

   Use print for same line, println for new line = A [OK]

Hint: Use print for same line, println to move to next line [OK]

Common Mistakes:

• Using println for each number causing new lines
• Using print after println without newline
• Adding \n inside print incorrectly