Strings und Kontrollfluss

fun main() {
    val s = "Hallo Welt"
    println("${s.length} ${s[0]} ${s.last()} ${s.substring(0, 5)} ${s.toUpperCase()} ${s.toLowerCase()}")
    println(s.replace("Welt", "Kotlin"))
    println(s.contains("Welt"))
    println(s.startsWith("Hal"))
    println(s.indexOf('W'))
    println(s.split(" "))
    println(s.reversed())
    println("  x ".trim() + "|")
    println("ab".repeat(3))
    println("a,b;c".split(",", ";"))
    println("kotlin".capitalize())
    println(s.take(5) + "-" + s.drop(6))
    println("Mia" + " " + 17)
    println("42".padStart(5, '0'))
    println("abc" < "abd")
    println("Name: %s, Alter: %d".format("Mia", 17))
    println(listOf("x", "y", "z").joinToString(" | "))

    val roh = """
        Mehrzeilig,
        "Anführungszeichen" und \n bleiben roh.
    """.trimIndent()
    println(roh)
    println("Tab:\tText \\ \" A")
}

fun main() {
    val sb = StringBuilder()
    for (i in 1..5) sb.append(i).append(',')
    sb.setLength(sb.length - 1)
    println(sb)
    println(buildString { append("a"); append("b") })
    val a = "x"; val b = "x"
    println(a == b)
}

fun main() {
    val punkte = 78
    if (punkte >= 90) {
        println("sehr gut")
    } else if (punkte >= 75) {
        println("gut")
    } else {
        println("weiter üben")
    }
    val ergebnis = if (punkte >= 50) "bestanden" else "durchgefallen"   // statt ternärem Operator
    println(ergebnis)
    println(maxOf(3, 8))
}

fun beschreibe(x: Any): String = when (x) {
    0 -> "null"
    1, 2, 3 -> "klein"
    in 4..9 -> "mittel"
    is Int -> "große Zahl"
    is String -> "Text mit ${x.length} Zeichen"
    is List<*> -> "Liste mit ${x.size} Elementen"
    else -> "unbekannt"
}

fun main() {
    for (v in listOf(0, 2, 7, 100, "Hallo", listOf(1, 2), 3.5)) println("$v: ${beschreibe(v)}")

    val note = 87
    val buchstabe = when {
        note >= 90 -> "A"
        note >= 80 -> "B"
        else -> "C"
    }
    println(buchstabe)
}

fun main() {
    for (i in 1..3) print("$i ")
    println()
    for (i in 10 downTo 1 step 4) print("$i ")
    println()
    for (i in 0 until 3) print("$i ")
    println()
    for ((index, wert) in listOf("a", "b", "c").withIndex()) print("$index=$wert ")
    println()
    for (c in "Kotlin") print("$c.")
    println()

    var n = 3
    while (n > 0) { print("$n "); n-- }
    println()
    do { n++ } while (n < 3)
    println(n)

    aussen@ for (i in 1..3) {
        for (j in 1..3) {
            if (j == 2) continue@aussen
            if (i == 3) break@aussen
            print("$i$j ")
        }
    }
    println()
    repeat(3) { print("*") }
    println()
}