Introduction
The while
loop in Kotlin is used to repeatedly execute a block of code as long as a specified condition is true. It is a fundamental control flow statement that allows for repeated execution of a block of code based on a condition. This chapter will cover the syntax and usage of the while
loop in Kotlin with examples.
Basic while Loop
The while
loop evaluates a condition before executing the loop body. If the condition is true, the loop body is executed. This process repeats until the condition becomes false.
Syntax
while (condition) {
// Code to execute as long as condition is true
}
- condition: A Boolean expression that is evaluated before each iteration of the loop.
- block of code: The set of instructions that will be executed repeatedly as long as the condition is true.
Example
fun main() {
var i = 1
while (i <= 5) {
println("Iteration $i")
i++
}
}
Explanation:
var i = 1
: Initializes a variablei
with the value 1.while (i <= 5)
: Checks ifi
is less than or equal to 5. Sincei
is 1, the condition is true, and the loop body executes.println("Iteration $i")
: Prints the current value ofi
.i++
: Increments the value ofi
by 1.- The loop continues until
i
becomes greater than 5.
Using break and continue in while Loop
break
Statement
The break
statement is used to terminate the loop immediately, regardless of the loop condition.
Example
fun main() {
var i = 1
while (i <= 5) {
if (i == 3) {
break
}
println("Iteration $i")
i++
}
}
Explanation:
- When
i
equals 3, thebreak
statement is executed, and the loop terminates. - The output will be:
Iteration 1 Iteration 2
continue
Statement
The continue
statement skips the current iteration of the loop and proceeds to the next iteration.
Example
fun main() {
var i = 1
while (i <= 5) {
if (i == 3) {
i++
continue
}
println("Iteration $i")
i++
}
}
Explanation:
- When
i
equals 3, thecontinue
statement is executed, skipping the rest of the loop body for that iteration. - The output will be:
Iteration 1 Iteration 2 Iteration 4 Iteration 5
Example Program using while Loop
fun main() {
// Basic while loop
println("Basic while loop:")
var i = 1
while (i <= 5) {
println("Iteration $i")
i++
}
// while loop with break
println("\nwhile loop with break:")
var k = 1
while (k <= 5) {
if (k == 3) {
break
}
println("Iteration $k")
k++
}
// while loop with continue
println("\nwhile loop with continue:")
var l = 1
while (l <= 5) {
if (l == 3) {
l++
continue
}
println("Iteration $l")
l++
}
}
Output
Basic while loop: Iteration 1 Iteration 2 Iteration 3 Iteration 4 Iteration 5 while loop with break: Iteration 1 Iteration 2 while loop with continue: Iteration 1 Iteration 2 Iteration 4 Iteration 5
Conclusion
In this chapter, you learned about the while
loop in Kotlin, including its syntax and usage for repeated execution of code blocks based on conditions. You also saw how to use the break
and continue
statements to control the flow within a loop. Understanding how to use these loops is essential for performing repetitive tasks and managing control flow in your Kotlin programs.