Kotlin If Else

The Basic if Statement

In Kotlin, the if statement executes a block of code only when a specified condition evaluates to true. The condition must be a Boolean expression, and unlike Java or C, Kotlin does not allow integers or other types to be used as a substitute for a Boolean condition.

fun main() {
    val temperature = 30

    if (temperature > 25) {
        println("It's a hot day")
    }
}

Adding else

The else branch runs when the if condition is false. Together, if and else let you cover both outcomes of a binary decision without repeating logic.

fun main() {
    val age = 16

    if (age >= 18) {
        println("You can vote")
    } else {
        println("You cannot vote yet")
    }
}

Chaining with else if

When you need to test several conditions in sequence, chain else if clauses. Kotlin evaluates each condition from top to bottom and executes the first branch whose condition is true, skipping the rest.

• Conditions are checked in order, top to bottom.
• Only the first matching branch runs — the rest are skipped.
• The final else acts as a catch-all for anything not matched above.

fun main() {
    val score = 72

    if (score >= 90) {
        println("Grade: A")
    } else if (score >= 75) {
        println("Grade: B")
    } else if (score >= 60) {
        println("Grade: C")
    } else {
        println("Grade: F")
    }
}

if as an Expression

This is where Kotlin diverges from languages like Java. Because if is an expression, it can return a value directly, which you can assign to a variable or return from a function. When used this way, an else branch is required so that the expression always produces a value.

fun main() {
    val a = 10
    val b = 20

    val max = if (a > b) a else b

    println("The larger number is $max")
}