Values and variables in Kotlin

val for bindings that never move, var for the few that must.

fun main() {
    // val binds once; var may be reassigned. Types are inferred.
    val ridge = "Sawtooth"
    var hikers = 4
    hikers += 2

    // Spell a type out when inference would pick the wrong one.
    val distanceKm: Double = 12.0
    val perLeg = distanceKm / hikers
    println("$hikers on $ridge, ${"%.1f".format(perLeg)} km each")
}

How it works

1. val ridge cannot be reassigned; var hikers can, and += updates it.
2. Types are inferred everywhere the initializer makes them obvious.
3. distanceKm: Double spells one out so the division stays fractional.

Keywords and builtins used here

• Double
• fun
• main
• val
• var

The run, in numbers

Lines

11

Characters to type

314

Tokens

59

Three-star pace

70 tpm

At the three-star pace of 70 tokens a minute, this run takes about 51 seconds.

Type this snippet

Step 2 of 3 in Values, step 2 of 27 in Language basics.

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