Generics demo

generics.kt

package com

class AnyList (val size: Int){
    val data: Array<Any?> = Array(size) { null }

    fun get(i: Int): Any? {
        return data[i]
    }

    fun put(i: Any?, where: Int) {
        data[where] = i
    }

    fun copy(): AnyList{
        val new = AnyList(size)
        for(i in 0 until size){
            new.put(data[i], i)
        }
        return new
    }

    override fun toString(): String {
        return "AnyList(data=${data.contentToString()})"
    }
}

class IntList (val size: Int){
    val data: Array<Int?> = Array(size) { null }

    fun get(i: Int): Int? {
        return data[i]
    }

    fun put(i: Int?, where: Int) {
        data[where] = i
    }

    fun copy(): IntList{
        val new = IntList(size)
        for(i in 0 until size){
            new.put(data[i], i)
        }
        return new
    }

    override fun toString(): String {
        return "IntList(data=${data.contentToString()})"
    }
}

class StringList (val size: Int){
    val data: Array<String?> = Array(size) { null }

    fun get(i: Int): String? {
        return data[i]
    }

    fun put(i: String?, where: Int) {
        data[where] = i
    }

    fun copy(): StringList{
        val new = StringList(size)
        for(i in 0 until size){
            new.put(data[i], i)
        }
        return new
    }

    override fun toString(): String {
        return "StringList(data=${data.contentToString()})"
    }
}

class GenericList<T> (private val size: Int){
    private val data = Array<Any?>(size) { null }

    fun get(i: Int): T {
        @Suppress("UNCHECKED_CAST")
        return data[i] as T
    }

    fun put(i: T, where: Int) {
        data[where] = i
    }

    fun copy(): GenericList<T>{
        val new = GenericList<T>(size)
        for(i in 0 until size){
            @Suppress("UNCHECKED_CAST")
            new.put(data[i] as T, i)
        }
        return new
    }

    override fun toString(): String {
        return "GenericList(data=${data.contentToString()})"
    }
}

fun mainOld() {
    val intList = IntList(4)
    intList.put(0, 0)
    intList.put(1, 1)
    intList.put(2, 2)
    println(intList.toString())

    val intListCopy = intList.copy()
    println(intListCopy.toString())

    val stringList = StringList(4)
    stringList.put("a", 0)
    stringList.put("b", 1)
    stringList.put("c", 2)
    println(stringList.toString())

    val stringListCopy = stringList.copy()
    println(stringListCopy.toString())

    val anyList = AnyList(3)
    anyList.put(0,0)
    anyList.put(1,0)
    //anyList.put("a",1)
    println(anyList.toString())

    val first: Int = anyList.get(0) as Int
    val second: Int = anyList.get(1) as Int
}

data class MyClass(val a: Int, val b: String)

fun main(){
    val intList = GenericList<Int>(4)
    intList.put(0, 0)
    intList.put(1, 1)
    intList.put(2, 2)
    println(intList.toString())

    val intListCopy = intList.copy()
    println(intListCopy.toString())

    val stringList = GenericList<String>(4)
    stringList.put("a", 0)
    stringList.put("b", 1)
    stringList.put("c", 2)
    println(stringList.toString())

    val stringListCopy = stringList.copy()
    println(stringListCopy.toString())

    val myList = GenericList<MyClass>(2)
    myList.put(MyClass(1, "a"),0)
    myList.put(MyClass(2, "b"),1)
    println(myList.toString())
}