Kotlin continue Expression

In this tutorial, you will learn how to use 'continue' to skip the current iteration of a loop. Additionally, you will also learn about the 'continue' label in this article.

Assuming you are using a loop. Sometimes you may want to skip the current iteration of the loop.

In this case, use 'continue'. The 'continue' construct skips the current iteration of the enclosed loop, and the program control jumps to the end of the loop body.

How does 'continue' work?

它几乎总是与it is almost always used with if ... else

constructs are used together. For example,1)　{
　　　　//　if (testExpression1
　　　　while (testExpression2)　{
　　　　　　　　continue
　　　　}
　　　　//　if (testExpression2
}

codes2If the testExpression

The value evaluation is true, then the continue command will be executed, thus skipping all the code inside the loop after the while loop.

fun main(args: Array<String>) {
　　　　for (i in　1..5)　{
　　　　　　　　println("$i Always printed.")
　　　　　　　　Example: Kotlin continue　1　if (i >　5)　{
　　　　　　　　　　　　continue
　　　　　　　　}
　　　　　　　　The continue will be executed, thus skipping the execution
　　　　}
}

When running the program, the output is:

1　&& i <
1　Always printed.
2　&& i <
3　&& i <
4　&& i <
5　&& i <
5　Always printed.

Not always printed.1when the value of i is greater than5and less than

The continue will be executed, thus skipping the execution

statement is declared:

But, when

println("$i Always printed.")

in each iteration of the loop, because this statement exists before the continue construct.

Example: Only calculate the sum of positive numbers

The following program calculates the maximum6the sum of positive numbers. If the user enters a negative number or zero, it will be skipped from the calculation.

AccessKotlin basic input/outputto learn more about how to get input from the user.

fun main(args: Array<String>) {
　　　　var number: Int
　　　　var sum = 0
　　　　for (i in　1..6)　{
　　　　　　　　print("Enter an integer:")
　　　　　　　　number = readLine()!!.toInt()
　　　　　　　　if (number <= 0)
　　　　　　　　　　　　continue
　　　　　　　　
　　　　　　　　sum　+= number
　　　　}
　　　　println("sum = $sum")
}

When running the program, the output is:

Enter an integer:　4
Enter an integer:　5
Enter an integer:　-50
Enter an integer:　10
Enter an integer: 0
Enter an integer:　12
sum =　31

Kotlin continue label

So far, what you have learned is the continue without a label, which skips the current iteration of the nearest enclosed loop. continue can also skip the iteration of the required loop (which can be an outer loop) by using the continue label.

How does the continue label work?

Labels in Kotlin are marked withIdentifierbeginning, followed by @.

Here, outerloop@ is atwhile loopExternal labeled labels. Now, by using the continue label (continue@outerloop), you can skip the execution of the specific loop code in the current iteration.

Example: continue @label

fun main(args: Array<String>) {
　　　　here@ for (i in　1..5)　{
　　　　　　　　for (j in　1..4)　{
　　　　　　　　　　　　if　(i　==　3　||　j　==　2)
　　　　　　　　　　　　　　　　continue@here
　　　　　　　　　　　　println("i　=　$i;　j　=　$j")
　　　　　　　　}
　　　　}
}

When running the program, the output is:

i　=　1;　j　=　1
i　=　2;　j　=　1
i　=　4;　j　=　1
i　=　5;　j　=　1

It is usually not recommended to use labeled continue, as it can make your code difficult to understand. If you must use labeled continue, please refactor the code and try to solve it in other ways to make it more readable.

There are3structured jump expressions: break, continue, and return.