Basic Kotlin
Variables data types
<![CDATA[var myNumber = 10 // Int
var myDecimal = 1.0 // Float
var isActive = true // Boolean
var myString: String // Mutable String
myString = "Hello World"
myString = "Another World"
val myAnotherString = "My constant string value" // Immutable String
// myAnotherString = "some value" // NOT ALLOWED, since it is immutable
var name: String
name = "Kevin"
var age: Int = 10
var myAge = 10
var isAlive: Boolean = true
var marks: Float = 97.4F
var percentage: Double = 90.78
var gender: Char = 'M'
]]>
Class
<![CDATA[
fun main(args: Array<String>) {
var personObj = Person()
personObj.name = "Steve"
print("The name of the person is ${personObj.name}")
}
class Person {
var name: String = ""
}
]]>
Another example
<![CDATA[
fun main(args: Array<String>) {
var personObj = Persson("Steve")
personObj.display()
}
class Persson(var name: String ) {
fun display() {
print("The name of the person is ${name}")
}
}
]]>
Explore String Interpolation in Kotlin
<![CDATA[
fun main(args: Array<String>) {
var rect = Rectangle()
rect.length = 5
rect.breadth = 3
print("The length of the rectangle is ${rect.length} and breadth is ${rect.breadth}. The area is ${rect.length * rect.breadth}")
}
class Rectangle {
var length: Int = 0
var breadth: Int = 0
}
]]>
Ranges
<![CDATA[
fun main(args: Array<String>) {
var r1 = 1..5
// This range contains number 1, 2, 3, 4, 5
val r2 = 5 downTo 1
// This range contains number 5, 4, 3, 2, 1
val r3 = 5 downTo 1 step 2
// This range contains number 5, 3, 1
val r4 = 'a'..'z'
// This range contains the values from "a", "b", "c" . . . "z"
var isPresent = 'c' in r4
var countDown = 10.downTo(1)
// This range contains number 10, 9, 8, 7, 6, 5, 4, 3, 2, 1
var moveUp = 1.rangeTo(10)
// This range contains number 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
}
]]>