Kotlin unlabelled continue

In this article, we will learn how to use continue in Kotlin. While working with loops in programming, sometimes, it is desirable to skip the current iteration of the loop. In that case, we can use the continue statement in the program. continue is used to repeat the loop for a specific condition. It skips the following statements and continues with the next iteration of the loop.

There are two types of continue in Kotlin.
We are going to learn how to use unlabelled continue in while, do-while, and for loops.

Use of unlabelled continue in a while loop

In Kotlin, unlabelled continue is used to skip the current iteration of the nearest enclosing while loop. If the condition for continue is true, then it skips the following instructions of continue and reaches to the starting of while loop. Again, it will check for the condition and loop will be in repetition mode until it becomes false.

Syntax of unlabelled continue in a while loop

while(condition) {
    //code
      if(condition for continue) {
      continue
      }
   //code
}

Flowchart
 

Kotlin program to use the continue in a while loop

fun main(args: Array<String>) {
    var num = 0
    while (num <= 12) {
        if (num % 3 == 0) {
            num++
            continue
        }
        println(num)
        num++
    }
}

Output:

1
2
4
5
7
8
10
11

Here, in the above program, we print the numbers and skips all multiples of 3. The expression (num % 3 == 0) is used to check that number is divisible by 3 or not. If it is multiple of 3 then increment the number without printing it to standard output.
 

Use of unlabelled continue in a do-while loop

In do-while also we can also use the unlabelled continue to skip the iteration of the nearest closing loop. Here, we need to put the condition for continue in do block. If condition becomes false it will skip the following instruction and transfer control to the while condition.

Syntax of unlabelled continue in a do-while loop

do{
     // codes 
     if(condition for continue) {
     continue
     }
} 
while(condition)

Flowchart

Kotlin program to use continue in a do-while loop

fun main(args: Array<String>) {
    var num = 1
    do {
        if (num <= 5 || num >=15) {
            num++
            continue
        }
        println("$num")
        num++
    } while (num < 20)
}

Output :

6
7
8
9
10
11
12
13
14

In the above program, we have used the condition (num <= 5 || num >=15) to skip the printing of numbers to the standard output which is less than or equal to 5 and greater than or equal to 15. So, it only prints the numbers from 6 to 14.
 

Use of unlabelled continue in a for loop

In a for loop, we can also use unlabelled continue to skip the current iteration to the closing loop. In the program below, we have taken an array of strings and i the iterator for the traversal of the array planets. The expression ( i < 2 ) skips the iteration of array indices less than two, which means it does not print the strings stored at index 0 and 1.

Syntax for unlabelled continue in a for loop

for(iteration through iterator) 
{  
   //code
   if(condition for continue){
   continue
   }
}

Flowchart

Kotlin program to use continue in a for loop

fun main(args: Array<String>) {

    var planets = arrayOf("Earth", "Mars", "Venus", "Jupiter", "Saturn")
    for (i in planets.indices) {
    
        if(i < 2){
            continue
        }
        println(planets[i])
    }
}

Output:

Venus
Jupiter
Saturn