Kotlin

fun main() {
    println("Hello, World!")
}

Datatypes

var number = 5
val constant = 5 //val is final

//it's possible to specify a type
val myNum: Int = 5                // Int
val myDoubleNum: Double = 5.99    // Double
val myLetter: Char = 'D'          // Char
val myBoolean: Boolean = true     // Boolean
val myText: String = "Hello"      // String

Operators

Arithmetic

Operator	Name	Example
+	Addition	x + y
-	Subtraction	x - y
*	Multiplication	x * y
/	Division	x / y
%	Modulus	x % y
++	Increment	i++
–	Decrement	i--

Assignment

Operator	Example	Same As
=	x = 5	x + y
+=	x += 5	x = x + 5
-=	x -= 5	x = x - 5
*=	x *= 5	x = x * 5
/=	x /= 5	x = x / 5
%=	x %= 5	x = x % 5

Comparison

Operator	Name	Example
==	equal to	x == y
!=	not equal to	x != y
>	greater than	x > y
<	less than	x < y
>=	greater than or equal to	x >= y
<=	less than or equal to	x <= y

Logical

Operator	Name	Description	Example
&&	AND	returns true if both statements are true	x < 5 && x < 10
||	OR	returns true if one of the statements is true	x < 5 || x < 4
!	NOT	reverse the result, returns false if the result is true	!(x < 5 && x < 10)