Kotlin break and continue

Inside a loop, you sometimes need to stop the loop early or skip one iteration. Kotlin gives you two tools: break exits the loop completely, and continue skips only the current round and moves to the next.

break — Exit the Loop Early

for (i in 1..10) {
    if (i == 6) break
    println(i)
}

Output:

1
2
3
4
5

The loop stops completely when i reaches 6. Numbers 6 through 10 are never printed.

continue — Skip One Iteration

for (i in 1..10) {
    if (i % 2 == 0) continue   // skip even numbers
    println(i)
}

Output:

1
3
5
7
9

Each even number triggers continue, which jumps straight to the next value of i. The println line is skipped for those values.

Diagram: break vs continue

i = 1  → print 1
i = 2  → even → continue → jump to i = 3
i = 3  → print 3
i = 4  → even → continue → jump to i = 5
i = 5  → print 5
i = 6  → if break: STOP LOOP ENTIRELY
         if continue: jump to i = 7

break in a while Loop

var balance = 1000
var day = 0

while (true) {
    day++
    balance -= 150    // spend 150 per day

    if (balance <= 0) {
        println("Money ran out on day $day")
        break
    }
}
// Output: Money ran out on day 7

Labeled break — Escape Nested Loops

By default, break exits only the innermost loop. Use a label to break out of an outer loop:

outer@ for (row in 1..4) {
    for (col in 1..4) {
        if (row == 2 && col == 3) {
            println("Breaking at row=$row, col=$col")
            break@outer    // exits both loops
        }
        print("($row,$col) ")
    }
    println()
}

Output:

(1,1) (1,2) (1,3) (1,4)
(2,1) (2,2) Breaking at row=2, col=3

Labeled continue — Skip in Outer Loop

outer@ for (i in 1..3) {
    for (j in 1..3) {
        if (j == 2) continue@outer   // skip rest of outer loop iteration
        println("i=$i, j=$j")
    }
}

Output:

i=1, j=1
i=2, j=1
i=3, j=1

When j equals 2, continue@outer skips the rest of the inner loop and jumps to the next i value immediately.

Practical Example: Find First Prime

fun main() {
    var found = false

    outer@ for (num in 2..100) {
        for (divisor in 2 until num) {
            if (num % divisor == 0) continue@outer  // not prime, try next num
        }
        println("First prime found: $num")
        found = true
        break  // stop after finding the first prime
    }
}

Output:

First prime found: 2