Created
November 15, 2019 09:46
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| package kz.technodom.merchant.service | |
| //Simple hello world | |
| fun main() { | |
| println("Hello, World") | |
| printMessage("Hello!") | |
| printMessageWithPrefix("Hello", "Toxa") | |
| printMessageWithPrefix("Hello2" ) | |
| multiply(2,3) | |
| //infix functions | |
| println("dude ".repeat(3)) | |
| infix fun Int.times (str:String) = str.repeat(this) | |
| println(3 times "Bob ") | |
| printAll("test1", "test2", "test3") | |
| //variables | |
| val a : String = "teststring" | |
| val b = "kotlin" | |
| var x : Int = 5 | |
| x =4 | |
| //null safety | |
| var str : String ? = "Koltin tutorial" | |
| str = null | |
| //safe call ?. | |
| length(str) | |
| //bob?.department?.head?.name | |
| val listWithNulls : List<String?> = mutableListOf("MutTest", null, "Modric") | |
| for ( l in listWithNulls){ | |
| l?.let { println(it) } | |
| } | |
| //elvis operator | |
| val be : String ? = null | |
| val l = if (be != null) be.length else -1 | |
| val c = be?.length ?: -1 | |
| val p = Person("Alice") | |
| println(p.name) | |
| p.name = "New name" | |
| val ani = Car(1, "monkey") | |
| println(ani) | |
| //inheritance | |
| val dog: Animal = Dog() | |
| dog.makeSound() | |
| val list = listOf("1", "2", "3") | |
| list.midElement() | |
| } | |
| fun length (str : String?) : Int? { | |
| return str?.length | |
| } | |
| fun printMessage(message:String){ | |
| println(message) | |
| } | |
| fun printMessageWithPrefix(message : String, info : String = "Info"){ | |
| println("[$info] $message") | |
| } | |
| fun sum (x:Int, y:Int) : Int{ | |
| return x + y | |
| } | |
| fun multiply(x : Int, y: Int) = x * y | |
| //Varargs allow you to pass any number of arguments by separating them with commas. | |
| fun printAll(vararg messages : String){ | |
| for (m in messages){ | |
| println(m) | |
| } | |
| } | |
| //classes | |
| class Customer | |
| class Person(var name: String){ | |
| fun printName(){ | |
| println(name) | |
| } | |
| } | |
| data class Car (val id: Long, val name: String) | |
| //Kotlin classes are final by default, in order to make them inheritable mark them as open classes | |
| open class Animal(){ | |
| open fun makeSound(){ | |
| println("def def") | |
| } | |
| } | |
| class Dog : Animal() { | |
| override fun makeSound() { | |
| println("au au") | |
| } | |
| } | |
| class Cat : Animal() { | |
| override fun makeSound() { | |
| println("miau miau") | |
| } | |
| } | |
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| package kz.technodom.merchant.service | |
| import java.lang.StringBuilder | |
| fun Int.abs() : Int = if (this < 0) -this else this | |
| fun List<String>.midElement() : String { | |
| if (this.isEmpty()){ | |
| throw NoSuchElementException("List is empty") | |
| } | |
| return this[this.size/2] | |
| } | |
| fun main() { | |
| val sb = StringBuilder() | |
| sb.append("yo") | |
| println("sb is $sb") | |
| cases("Hello") | |
| val cakes = listOf("one", "two", "three") | |
| for (c in cakes){ | |
| println(c) | |
| } | |
| for (i in 1..3){ | |
| println(i) | |
| } | |
| for (i in 2..8 step 2){ | |
| println(i) | |
| } | |
| val authors = setOf("Shakespeare", "Hemingway", "Twain") | |
| val writers = setOf("Twain", "Shakespeare", "Hemingway") | |
| println(authors == writers) | |
| println(authors === writers) | |
| val map = mapOf("One" to 1, "Two" to 2) | |
| val x = -5 | |
| println(x.abs()) | |
| val colors = listOf("blue", "red", "yellow") | |
| println(colors.midElement() ) | |
| } | |
| fun cases(obj:Any){ | |
| when(obj) { | |
| 1 -> println("One") | |
| "Hello"-> println("Greeting") | |
| is Long -> println("$obj is long") | |
| !is String -> println("Not a string") | |
| else -> println("Unknown") | |
| } | |
| } | |
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