println("Hello, world!")

println("Hello, world!")

var myVariable = 42
myVariable = 50
val myConstant = 42

var myVariable = 42
myVariable = 50
val myConstant = 42

val explicitDouble: Double = 70.0

val explicitDouble: Double = 70.0

val label = "The width is "
val width = 94
val widthLabel = label + width

val label = "The width is "
val width = 94
val widthLabel = label + width

val apples = 3
val oranges = 5
val fruitSummary = "I have ${apples + oranges} " +
                   "pieces of fruit."

val apples = 3
val oranges = 5
val fruitSummary = "I have ${apples + oranges} " +
                   "pieces of fruit."

val names = arrayOf("Anna", "Alex", "Brian", "Jack")
val count = names.count()
for (i in 0..count - 1) {
    println("Person ${i + 1} is called ${names[i]}")
}
// Person 1 is called Anna
// Person 2 is called Alex
// Person 3 is called Brian
// Person 4 is called Jack

val names = arrayOf("Anna", "Alex", "Brian", "Jack")
val count = names.count()
for (i in 0..count - 1) {
    println("Person ${i + 1} is called ${names[i]}")
}
// Person 1 is called Anna
// Person 2 is called Alex
// Person 3 is called Brian
// Person 4 is called Jack

for (index in 1..5) {
    println("$index times 5 is ${index * 5}")
}
// 1 times 5 is 5
// 2 times 5 is 10
// 3 times 5 is 15
// 4 times 5 is 20
// 5 times 5 is 25

for (index in 1..5) {
    println("$index times 5 is ${index * 5}")
}
// 1 times 5 is 5
// 2 times 5 is 10
// 3 times 5 is 15
// 4 times 5 is 20
// 5 times 5 is 25

val shoppingList = arrayOf("catfish", "water",
    "tulips", "blue paint")
shoppingList[1] = "bottle of water"

val shoppingList = arrayOf("catfish", "water",
    "tulips", "blue paint")
shoppingList[1] = "bottle of water"

val occupations = mutableMapOf(
    "Malcolm" to "Captain",
    "Kaylee" to "Mechanic"
)
occupations["Jayne"] = "Public Relations"

val occupations = mutableMapOf(
    "Malcolm" to "Captain",
    "Kaylee" to "Mechanic"
)
occupations["Jayne"] = "Public Relations"

val emptyArray = arrayOf<String>()
val emptyMap = mapOf<String, Float>()

val emptyArray = arrayOf<String>()
val emptyMap = mapOf<String, Float>()

fun greet(name: String, day: String): String {
    return "Hello $name, today is $day."
}
greet("Bob", "Tuesday")

fun greet(name: String, day: String): String {
    return "Hello $name, today is $day."
}
greet("Bob", "Tuesday")

data class GasPrices(val a: Double, val b: Double,
     val c: Double)
fun getGasPrices() = GasPrices(3.59, 3.69, 3.79)

data class GasPrices(val a: Double, val b: Double,
     val c: Double)
fun getGasPrices() = GasPrices(3.59, 3.69, 3.79)

fun sumOf(vararg numbers: Int): Int {
    var sum = 0
    for (number in numbers) {
        sum += number
    }
    return sum
}
sumOf(42, 597, 12)

// sumOf() can also be written in a shorter way:
fun sumOf(vararg numbers: Int) = numbers.sum()

fun sumOf(vararg numbers: Int): Int {
    var sum = 0
    for (number in numbers) {
        sum += number
    }
    return sum
}
sumOf(42, 597, 12)

// sumOf() can also be written in a shorter way:
fun sumOf(vararg numbers: Int) = numbers.sum()

fun makeIncrementer(): (Int) -> Int {
    val addOne = fun(number: Int): Int {
        return 1 + number
    }
    return addOne
}
val increment = makeIncrementer()
increment(7)

// makeIncrementer can also be written in a shorter way:
fun makeIncrementer() = fun(number: Int) = 1 + number

fun makeIncrementer(): (Int) -> Int {
    val addOne = fun(number: Int): Int {
        return 1 + number
    }
    return addOne
}
val increment = makeIncrementer()
increment(7)

// makeIncrementer can also be written in a shorter way:
fun makeIncrementer() = fun(number: Int) = 1 + number

val numbers = listOf(20, 19, 7, 12)
numbers.map { 3 * it }

val numbers = listOf(20, 19, 7, 12)
numbers.map { 3 * it }

listOf(1, 5, 3, 12, 2).sorted()

listOf(1, 5, 3, 12, 2).sorted()

fun area(width: Int, height: Int) = width * height
area(width = 2, height = 3)

// This is also possible with named arguments
area(2, height = 2)
area(height = 3, width = 2)

fun area(width: Int, height: Int) = width * height
area(width = 2, height = 3)

// This is also possible with named arguments
area(2, height = 2)
area(height = 3, width = 2)

class Shape {
    var numberOfSides = 0
    fun simpleDescription() =
        "A shape with $numberOfSides sides."
}

class Shape {
    var numberOfSides = 0
    fun simpleDescription() =
        "A shape with $numberOfSides sides."
}

var shape = Shape()
shape.numberOfSides = 7
var shapeDescription = shape.simpleDescription()

var shape = Shape()
shape.numberOfSides = 7
var shapeDescription = shape.simpleDescription()

open class NamedShape(val name: String) {
    var numberOfSides = 0

    open fun simpleDescription() =
        "A shape with $numberOfSides sides."
}

class Square(var sideLength: BigDecimal, name: String) :
        NamedShape(name) {
    init {
        numberOfSides = 4
    }

    fun area() = sideLength.pow(2)

    override fun simpleDescription() =
        "A square with sides of length $sideLength."
}

val test = Square(BigDecimal("5.2"), "square")
test.area()
test.simpleDescription()

open class NamedShape(val name: String) {
    var numberOfSides = 0

    open fun simpleDescription() =
        "A shape with $numberOfSides sides."
}

class Square(var sideLength: BigDecimal, name: String) :
        NamedShape(name) {
    init {
        numberOfSides = 4
    }

    fun area() = sideLength.pow(2)

    override fun simpleDescription() =
        "A square with sides of length $sideLength."
}

val test = Square(BigDecimal("5.2"), "square")
test.area()
test.simpleDescription()

var movieCount = 0
var songCount = 0

for (item in library) {
    if (item is Movie) {
        ++movieCount
    } else if (item is Song) {
        ++songCount
    }
}

var movieCount = 0
var songCount = 0

for (item in library) {
    if (item is Movie) {
        ++movieCount
    } else if (item is Song) {
        ++songCount
    }
}

for (current in someObjects) {
    if (current is Movie) {
        println("Movie: '${current.name}', " +
	    "dir. ${current.director}")
    }
}

for (current in someObjects) {
    if (current is Movie) {
        println("Movie: '${current.name}', " +
	    "dir. ${current.director}")
    }
}

interface Nameable {
    fun name(): String
}

fun f<T: Nameable>(x: T) {
    println("Name is " + x.name())
}

interface Nameable {
    fun name(): String
}

fun f<T: Nameable>(x: T) {
    println("Name is " + x.name())
}