Break and continue behavior in Kotlin - Mini Project: Build & Apply

Break and continue behavior

📖 Scenario: You are organizing a small event and have a list of guests with their ages. You want to process this list to find guests who are adults and stop checking once you find a guest who is exactly 21 years old. You also want to skip any guests who are under 18.

🎯 Goal: Build a Kotlin program that uses break and continue statements inside a for loop to process a list of guest ages. The program should skip guests under 18, stop processing when a guest aged 21 is found, and print the ages of guests processed.

📋 What You'll Learn

Create a list of guest ages called guestAges with the exact values: 16, 17, 18, 19, 20, 21, 22

Create a variable called processedAges as an empty mutable list of integers

Use a for loop with variable age to iterate over guestAges

Inside the loop, use continue to skip ages less than 18

Inside the loop, use break to stop the loop when age equals 21

Add each processed age to processedAges

Print the processedAges list at the end

💡 Why This Matters

🌍 Real World

This project shows how to control loops when processing lists, which is common when filtering or searching data like guest lists, orders, or sensor readings.

💼 Career

Understanding break and continue helps in writing efficient code that can skip unnecessary work or stop early, important skills for software developers and data analysts.

1

Create the guest ages list

Create a list called guestAges with these exact integer values: 16, 17, 18, 19, 20, 21, 22.

Kotlin

# Create the guestAges list with the exact values
# Your code here

Hint

Use listOf to create a list with the exact ages.

2

Create the processed ages list

Create a mutable list of integers called processedAges and initialize it as empty.

Kotlin

val guestAges = listOf(16, 17, 18, 19, 20, 21, 22)
# Create an empty mutable list called processedAges
# Your code here

Hint

Use mutableListOf<Int>() to create an empty mutable list of integers.

3

Process the guest ages with break and continue

Use a for loop with variable age to iterate over guestAges. Inside the loop, use continue to skip ages less than 18. Use break to stop the loop when age equals 21. Add each processed age to processedAges.

Kotlin

val guestAges = listOf(16, 17, 18, 19, 20, 21, 22)
val processedAges = mutableListOf()
# Add a for loop to iterate over guestAges
# Use continue to skip ages less than 18
# Use break to stop when age is 21
# Add each processed age to processedAges
# Your code here

Hint

Use for (age in guestAges) to loop. Use continue and break as needed.

4

Print the processed ages list

Write a println statement to print the processedAges list.

Kotlin

val guestAges = listOf(16, 17, 18, 19, 20, 21, 22)
val processedAges = mutableListOf()
for (age in guestAges) {
    if (age < 18) continue
    if (age == 21) break
    processedAges.add(age)
}
# Print the processedAges list
# Your code here

Hint

Use println(processedAges) to display the list.

Practice

1. What does the break statement do inside a Kotlin loop?

easy

A. Stops the entire loop immediately

B. Skips the current iteration and continues the loop

C. Restarts the loop from the beginning

D. Pauses the loop until a condition is met

Solution

1. Step 1: Understand the role of break

   The break statement immediately stops the whole loop when executed.

2. Step 2: Compare with other loop controls

   Unlike continue, which skips only the current step, break ends the loop fully.

3. Final Answer:

   Stops the entire loop immediately -> Option A

4. Quick Check:

   break stops loop = B [OK]

Hint: Remember: break = stop loop, continue = skip step [OK]

Common Mistakes:

• Confusing break with continue
• Thinking break skips only one iteration
• Assuming break restarts the loop

2. Which of the following is the correct syntax to skip the current iteration in a Kotlin for loop?

easy

A. continue

B. break

C. skip

D. stop

Solution

1. Step 1: Identify the keyword to skip iteration

   In Kotlin, continue is used to skip the current loop iteration and move to the next.

2. Step 2: Check other options for correctness

   break stops the loop, skip and stop are not valid Kotlin keywords.

3. Final Answer:

   continue -> Option A

4. Quick Check:

   Skip iteration = continue [OK]

Hint: Use continue to skip steps inside loops [OK]

Common Mistakes:

• Using break instead of continue
• Using non-existent keywords like skip or stop
• Confusing syntax with other languages

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

for (i in 1..5) {
    if (i == 3) break
    print(i)
}

medium

A. Error

B. 12345

C. 345

D. 12

Solution

1. Step 1: Analyze the loop and break condition

   The loop runs from 1 to 5. When i equals 3, break stops the loop immediately.

2. Step 2: Determine printed values before break

   Values 1 and 2 are printed before hitting i == 3, then loop stops.

3. Final Answer:

   12 -> Option D

4. Quick Check:

   Loop stops at 3, prints 1 and 2 [OK]

Hint: Break stops loop before printing 3 [OK]

Common Mistakes:

• Assuming 3 is printed before break
• Thinking loop continues after break
• Confusing break with continue

4. Find the error in this Kotlin code snippet:

for (i in 1..5) {
    if (i == 3) continue
    if (i == 6) break
    print(i)
}

medium

A. The loop will run infinitely

B. continue cannot be used inside for loops

C. The break condition is unreachable

D. Syntax error in if statements

Solution

1. Step 1: Check loop range and conditions

   The loop runs from 1 to 5, so i == 6 never happens.

2. Step 2: Analyze break condition reachability

   Since i never reaches 6, the break statement is never executed, making it unreachable code.

3. Final Answer:

   The break condition is unreachable -> Option C

4. Quick Check:

   Break at i=6 unreachable in 1..5 loop [OK]

Hint: Check loop range matches break condition [OK]

Common Mistakes:

• Assuming break will run at i=6
• Thinking continue is invalid in loops
• Believing loop runs infinitely

5. Consider this Kotlin code:

var sum = 0
for (i in 1..10) {
    if (i % 2 == 0) continue
    if (sum > 10) break
    sum += i
}
print(sum)

What is the output?

hard

A. 25

B. 11

C. 9

D. 16

Solution

1. Step 1: Understand loop behavior with continue and break

   The loop adds only odd numbers (because even numbers are skipped by continue). It stops when sum > 10.

2. Step 2: Calculate sum step-by-step

   Odd numbers: 1,3,5,7,9
   i=1: sum=0 <=10, sum=1
   i=3: sum=1 <=10, sum=4
   i=5: sum=4 <=10, sum=9
   i=7: sum=9 <=10, sum=16
   i=9: sum=16 >10, break (no add 9).

3. Final Answer:

   11 -> Option B

4. Quick Check:

   Sum odd numbers until sum > 10 = 11 [OK]

Hint: Add odds, stop when sum exceeds 10 [OK]

Common Mistakes:

• Adding even numbers mistakenly
• Breaking before sum exceeds 10
• Miscounting sum steps