Kotlin:
*variables*
var age = 0 // implicit var declaration
var isCompleted = false // explicit var declaration
val test = 3; // constant
*strings*
var s1:String = "hello"
val result:String = "hello $name"
*classes*
class MyClass: Any() {
var myProperty = 12
// methodes
}
val mClass = MyClass() // object instance
*methods*
fun myMethod(): Boolean? {
return true
}
fun methodWithParams(a: Int, b: Int): Int {
return a + b
}
*varargs*
fun sum1(vararg values: Int): Int {
var total = 0
for (i in values.indices) {
total += values[i]
}
return total
}
println(mClass.sum1(1,2,4))
*arraylist*
val cars = ArrayList<String>() // Create an ArrayList object
*array*
val num = Array(3, {i-> i*1})
val cars = arrayOf("Volvo", "BMW", "Ford", "Mazda")
// access element at index 0
cars[0] = "jag";
*dictionary*
import java.util.*
val dic1: Hashtable<String, Int> = Hashtable()
dic1["one"] = 1
dic1["two"] = 2
val e = dic1.keys()
while (e.hasMoreElements()) {
// Getting the key of a particular entry
val key = e.nextElement()
// Print and display the Rank and Name
println("key : " + key + " value " + dic1[key])
}
*if*
val time = 20
if (time < 18) {
println("Good day.")
} else {
println("Good evening.")
}
val s1:String = if (bool1) "true" else "false"
*** you are here
*loops*
for (i in 1..10) {}
for (i in arr) {} // for each item loop
while (bool) {}
do{}
while (bool)
*switch*
when (expression) {
"x" -> {}
"y" -> {}
else -> {}
}
*randomizer*
import java.util.*
val rand = Random() // instance of random class
val int_random: Int = rand.nextInt(upperbound) // 0->upperbound -1
val double_random: Double = rand.nextDouble() // 0->1
val float_random: Float = rand.nextFloat() //0->1
*N-dimensional arrays*
val arr = Array(10) { IntArray(20) }
arr[0][0] = 1