fun main() {
    // Arrays (Not in Collections)
    // Elements: 54, 0, 0, 0, 0 (Default value = Curly bracket value)
    var myArray = Array(5) { 0 } // Mutable Fixed Size
    myArray[0] = 32
    myArray[0] = 54

    // List
    var list = listOf("Mahmut", "Tuncer", "Serkan") // Immutable, Fixed Size, READ ONLY

    // MutableList
    var myMutableList = mutableListOf<String>() // Mutable, No Fixed Size, Can Add or Remove Elements
    myMutableList.add("Mahmut")
    myMutableList.add("Tuncer")
    myMutableList[0] = "Ahmet" // replace

    // ArrayList
    var myArrayList = arrayListOf<String>() // Mutable, No Fixed Size, Can Add or Remove Elements
    myArrayList.add("Mahmut")
    myArrayList.add("Tuncer")
    myArrayList[0] = "Ahmet" // replace

    // Map (K-V)
    var myMap = mapOf(2 to "Mahmut", 43 to "Tuncer", 7 to "Serkan") // Immutable, Fixed Size, READ ONLY

    for (key in myMap.keys) {
        println("Elements at key $key = ${myMap[key]}") // myMap.get()
    }

    // MutableMap (K-V)
    var myMutableMap = mutableMapOf<Int, String>() // Mutable, No Fixed Size, Can Add or Remove Elements
    myMutableMap.put(2, "Mahmut")
    myMutableMap.put(43, "Tuncer")
    myMutableMap.put(7, "Serkan")
    myMutableMap.replace(43, "Ahmet")

    // HashMap (K-V)
    var myHashMap = hashMapOf<Int, String>() // Mutable, No Fixed Size, Can Add or Remove Elements
    myHashMap.put(2, "Mahmut")
    myHashMap.put(43, "Tuncer")
    myHashMap.put(7, "Serkan")
    myHashMap.replace(43, "Ahmet")

    // "Set" contains unique elements (sequence)
    var mySet = setOf(2, 54, 9, 9, 9, 100) // Immutable READ ONLY

    // MutableSet (sequence)
    var myMutableSet = mutableSetOf<Int>() // READ and WRITE both
    myMutableSet.add(2)
    myMutableSet.add(54)
    myMutableSet.add(54)

    // "HashSet" also contains unique elements but sequence is not guaranteed in output
    var myHashSet = hashSetOf<Int>() // READ and WRITE both
    myHashSet.add(2)
    myHashSet.add(54)
    myHashSet.add(54)
}