📌 Control Flow in Kotlin

Control flow in Kotlin refers to the order in which statements are executed in a program. Kotlin provides several control flow statements for making decisions and repeating actions.

🔎 Types of Control Flow Statements

1. Conditional Statements

   • if and else

   • when (Similar to switch in other languages)

2. Looping Statements

   • for Loop

   • while Loop

   • do-while Loop

3. Jump Statements

   • break

   • continue

   • return

✅ 1. If-Else Statement

The if-else statement is used for decision-making.

📌 Syntax

kotlin
val number = 10if (number > 0) {    println("Positive number")} else {    println("Negative number or zero")}

Output:

typescript
Positive number

📌 If-Else as an Expression

In Kotlin, if-else can return a value and be used as an expression.

kotlin
val a = 15val b = 10val max = if (a > b) a else bprintln("Max: $max")

Output:

makefile
Max: 15

✅ 2. When Statement

The when statement in Kotlin is a more readable alternative to if-else-if chains. It works like a switch statement in other languages.

📌 Example

kotlin
val day = 3val dayName = when (day) {    1 -> "Monday"    2 -> "Tuesday"    3 -> "Wednesday"    4 -> "Thursday"    else -> "Invalid Day"}println(dayName)

Output:

mathematica
Wednesday

📌 When with Multiple Conditions

kotlin
val grade = 'B'when (grade) {    'A', 'B' -> println("Good job!")    'C' -> println("Can do better")    else -> println("Needs improvement")}

Output:

nginx
Good job!

✅ 3. For Loop

A for loop is used to iterate through a range, an array, or a collection.

📌 Example: Using Ranges

kotlin
for (i in 1..5) {    println(i) // Output: 1 to 5}

📌 Example: Using until

kotlin
for (i in 1 until 5) {    println(i) // Output: 1 to 4}

📌 Example: Iterating over Arrays

kotlin
val fruits = arrayOf("Apple", "Banana", "Cherry")for (fruit in fruits) {    println(fruit)}

Output:

nginx
AppleBananaCherry

✅ 4. While Loop

The while loop runs as long as the condition is true.

📌 Example:

kotlin
var i = 1while (i <= 5) {    println(i)    i++}

Output:

12345

✅ 5. Do-While Loop

A do-while loop runs at least once because the condition is checked after the code block executes.

📌 Example:

kotlin
do {    println(i)    i++} while (i <= 5)

Output:

12345

✅ 6. Break and Continue

• break → Exits the loop when a condition is met.

• continue → Skips the current iteration and moves to the next.

📌 Break Example

kotlin
for (i in 1..10) {    if (i == 5) {        println("Breaking at $i")        for (i in 1..5) {    if (i == 3) {        println("Skipping $i")        continue    }    println(i)}

Output:

12Skipping 345

✅ Conclusion

• If-else is great for simple conditions.

• When is a cleaner alternative to multiple if-else-if statements.

• For loops are efficient for iterating through ranges and collections.

• While and Do-While loops are used for repeated execution with condition checks.

• Break and Continue provide control over loop flow.