// for (item in collection) {
//     // code, that typically references item
//     // runs # times for |collection|
// }

fun loopingCharsInString() {
    for (c in "howdy") {
        println(c)
    }
}

fun loopingIntsInRangesProgressions() {
    for (num in 1..5) {
        val numSquared = num * num
        
        println("$num squared is $numSquared")
    }

    for (seconds in 5 downTo 1) {
        println("$seconds second(s) to go!")
    }
    println("Happy New Year!!")
}

fun loopingLists() {
    fun sayHello(name: String) {
        println("Howdy, $name!")
    }

    val characters = listOf("Harry", "Hermione", "Ron")

    for (student in characters) {
        sayHello(student)
    }
}

fun loopingMixed() {
    val letters = listOf("a", "b", "c")
    val numbers = listOf(1, 2, 3)

    for (idx in letters.indices) {
        println("At index $idx, you'll find '${ letters[ idx ] }'")
    }

    // last homework?
    for (idx in letters.indices) {
        println("easy as ${ letters[idx] }${ numbers[idx] }")
    }
}

fun loopingNested(names: List<String>, excitementLevel: Int) {
    for (name in names) {
        print("Hello, $name")
        
        for (num in 1..excitementLevel) {
            print("!")
        }
        println()
    }
}

fun main() {
    loopingCharsInString()
    loopingIntsInRangesProgressions()
    loopingLists()
    loopingMixed()

    loopingNested(
        listOf("alice", "bob", "chris"),
        7
    )
}

main()