Break and continue behavior in Kotlin

Introduction

Break and continue help control loops by stopping or skipping parts of the loop. They make your code easier to manage when you want to exit early or skip steps.

When you want to stop a loop as soon as a condition is met, like finding a specific item in a list.

When you want to skip certain steps in a loop, like ignoring invalid data but continuing with the rest.

When searching through data and you want to stop once you get the first match.

When processing user input and you want to skip empty or incorrect entries.

When you want to improve performance by not running unnecessary loop cycles.

Syntax

Kotlin

for (item in collection) {
    if (conditionToStop) {
        break
    }
    if (conditionToSkip) {
        continue
    }
    // other code
}

break stops the whole loop immediately.

continue skips the current loop step and moves to the next one.

Examples

This loop prints numbers 1 and 2, then stops when i is 3.

Kotlin

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

This loop skips printing 3 but prints all other numbers from 1 to 5.

Kotlin

for (i in 1..5) {
    if (i == 3) continue
    println(i)
}

This prints 'heo' by skipping the letter 'l'.

Kotlin

for (char in "hello") {
    if (char == 'l') continue
    print(char)
}

Sample Program

This program shows how break stops the loop when number 4 is reached, so it prints 1, 2, 3 only. Then it shows how continue skips printing 4 but continues printing the rest.

Kotlin

fun main() {
    val numbers = listOf(1, 2, 3, 4, 5)
    println("Using break:")
    for (num in numbers) {
        if (num == 4) {
            break
        }
        println(num)
    }

    println("Using continue:")
    for (num in numbers) {
        if (num == 4) {
            continue
        }
        println(num)
    }
}

Important Notes

Use break carefully because it stops the whole loop immediately.

continue only skips the current step, so the loop keeps running.

Both help make loops more efficient and easier to read.

Summary

break stops the entire loop right away.

continue skips the current loop step and moves on.

Use them to control loops clearly and avoid unnecessary work.

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