This document provides tips and tricks for installing Kotlin programming tools and covers fundamental Kotlin concepts like data types, variables, functions, control flow structures, and loops. It discusses installing Kotlin and resolving common errors. It introduces basic Kotlin syntax for strings, numbers, Booleans, arrays, and more. It also covers if/else expressions, when expressions, enums, loops like while, for, and for-each, and break/continue functionality. The document encourages practicing exercises to continue learning Kotlin.

1. Memulai
Pemrograman
dengan Kotlin
#2
Ahmad Arif Faizin
Academy Content Writer
Dicoding Indonesia
x

2. Tips Trik Seputar Instalasi
- Pastikan menggunakan versi yang sama dengan yang ada di modul.
- Jika sudah pernah menginstall Java sebelumnya, install dulu versi yang lama.
- Invalidate cache/restart jika tidak bisa run EduTools.
- Disable antivirus seperti Avast.
- Jika errornya “Failed to launch checking”, coba hapus folder project dan ulangi
mengambil course.
- Pastikan koneksi lancar saat instalasi.
- Kode merah-merah? pastikan besar kecil spasi sama dengan di modul.
- Untuk pengguna 32 bit bisa mencoba install JDK lewat Azul.com

4. 3.
Kotlin Fundamental
Tipe Data & Fungsi

5. Hello Kotlin!
// main function
fun main() {
println("Hello Kotlin!")
}
fungsi pertama ketika
program dijalankan
untuk memberi komentar
fungsi untuk mencetak teks
ke layar/console

6. println vs print
fun main() {
println("Kotlin, ")
print("is Awesome!")
}
/*
output:
Kotlin,
is Awesome
*/
fun main() {
print("Kotlin, ")
print("is Awesome!")
}
/*
output:
Kotlin, is Awesome
*/

7. Contoh lain
fun main() {
val name = "Arif"
print("Hello my name is ")
println(name)
print(if (true) "Always true" else "Always false")
}
/*
output:
Hello my name is Arif
Always true
*/
cetak teks ke layar
untuk membuat variabel dengan tipe data string
untuk membuat
percabangan
cetak teks ke layar dan
membuat baris baru

8. Cara Menulis Variabel
var namaVariabel: TipeData = isi(value)
Contoh :
var company: String = "Dicoding"
atau bisa disingkat
var company = "Dicoding"
tipe data akan
menyesuaikan dengan
isinya

9. var vs val
Bisa diubah nilainya
(mutable)
var company = "Dicoding"
company = "Dicoding Academy"
Tidak bisa diubah nilainya
(immutable)
val company = "Dicoding"
company = "Dicoding Academy"
//Val cannot be reassigned

10. Tipe Data
Char hanya satu karakter ‘A’
String kumpulan dari banyak karakter (teks) “Kotlin”
Array menyimpan banyak objek arrayOf(“Aku”, “Kamu”, “Dia”)
Numbers angka 7
Boolean hanya memiliki 2 nilai true/false

11. Char
Contoh :
val character: Char = 'A'
Contoh salah
val character: Char = 'ABC'
// Incorrect character literal

12. Char
Operator increment & decrement
fun main() {
var vocal = 'A'
println("Vocal " + vocal++)
println("Vocal " + vocal--)
println("Vocal " + vocal)
}
/*
output:
Vocal A
Vocal B
Vocal A
*/

13. String
Memasukkan variabel ke dalam String
Contoh :
fun main() {
val text = "Kotlin"
val firstChar = text[0]
print("First character of" + text + " is " + firstChar)
}
print("First character of $text is $firstChar") string template

14. String
Membuat pengecualian(escaped) di dalam String
Contoh :
val statement = "Kotlin is "Awesome!""

15. String
Membuat Raw String
Contoh :
fun main() {
val line = """
Line 1
Line 2
Line 3
Line 4
""".trimIndent()
print(line)
}
/*
output:
Line 1
Line 2
Line 3
Line 4
*/

16. Array
indeks dimulai dari 0
fun main() {
val intArray = intArrayOf(1, 3, 5, 7) // [1, 3, 5, 7]
intArray[2] = 11 // [1, 3, 11, 7]
print(intArray[2])
}
/*
Output: 11
*/
1 3 5 7
ke-0 ke-1 ke-2 ke-3

17. Boolean

18. Numbers
Int (32 bit) nilai angka yang umum digunakan val intNumbers = 100
Long (64 bit) nilai angka yang besar val longNumbers = 100L
Short (16 bit) nilai angka yang kecil val shortNumber: Short = 10
Byte (8 bit) nilai angka yang sangat kecil val byteNumber = 0b11010010
Double (64 bit) nilai angka pecahan val doubleNumbers = 1.3

19. Functions
tanpa nilai kembalian
fun main() {
setUser("Arif", 17)
}
fun setUser(name: String, age: Int){
println("Your name is $name, and you $age years old")
}
parameter yang dikirimkan
ke dalam fungsi
untuk membuat fungsi

20. Functions
dengan nilai kembalian
fun main() {
val user = setUser("Arif", 17)
println(user)
}
fun setUser(name: String, age: Int): String {
return "Your name is $name, and you $age years old"
}
untuk membuat nilai
kembalian
tipe data nilai yang
dikembalikan
fun setUser(name: String, age: Int) = "Your name is $name, and you $age years old"

21. If Expressions
percabangan berdasarkan kondisi
val openHours = 7
val now = 20
if (now > openHours){
println("office already open")
}
val openHours = 7
val now = 20
val office: String
if (now > openHours) {
office = "Office already open"
} else {
office = "Office is closed"
}
print(office)
val openHours = 7
val now = 7
val office: String
office = if (now > 7) {
"Office already open"
} else if (now == openHours){
"Wait a minute, office will be open"
} else {
"Office is closed"
}
print(office)

22. Nullable Types
Contoh:
val text: String? = null
Contoh salah:
val text: String = null
// compile time error

23. Safe Call Operator ?.
memanggil nullable dengan aman
val text: String? = null
text?.length
val text: String? = null
val textLength = text?.length ?: 7
Elvis Operator ?:
nilai default jika objek bernilai null

24. Kerjakan Latihan

25. 4.
Control Flow
Percabangan & Perulangan

26. When Expression
Percabangan selain If Else
fun main() {
val value = 7
val stringOfValue = when (value) {
6 -> "value is 6"
7 -> "value is 7"
8 -> "value is 8"
else -> "value cannot be reached"
}
println(stringOfValue)
}
/*
output : value is 7
*/

27. When Expression
val anyType : Any = 100L
when(anyType){
is Long -> println("the value has a Long type")
is String -> println("the value has a String type")
else -> println("undefined")
}
val value = 27
val ranges = 10..50
when(value){
in ranges -> println("value is in the range")
!in ranges -> println("value is outside the range")
else -> println("value undefined")
}
val x = 11
when (x) {
10, 11 -> print("the value between 10 and 11")
11, 12 -> print("the value between 11 and 12")
}
val x = 10
when (x) {
5 + 5 -> print("the value is 10")
10 + 10 -> print("the value is 20")
}

28. Enumeration
fun main() {
val color: Color = Color.GREEN
when(color){
Color.RED -> print("Color is Red")
Color.BLUE -> print("Color is Blue")
Color.GREEN -> print("Color is Green")
}
}
enum class Color(val value: Int) {
RED(0xFF0000),
GREEN(0x00FF00),
BLUE(0x0000FF)
}
//output : Color is Green

29. While
Perulangan
fun main() {
var counter = 1
while (counter <= 5){
println("Hello, World!")
counter++
}
}
fun main() {
println("Hello World")
println("Hello World")
println("Hello World")
println("Hello World")
println("Hello World")
}
=

30. fun main() {
var counter = 1
while (counter <= 7){
println("Hello, World!")
counter++
}
}
cek dulu
baru jalankan
While vs Do While
fun main() {
var counter = 1
do {
println("Hello, World!")
counter++
} while (counter <= 7)
}
jalankan dulu
baru cek

31. Hati - Hati dengan infinite loop
Karena kondisi tidak terpenuhi
var value = 'A'
do {
print(value)
} while (value <= 'Z')
var i = 3
while (i > 3) {
println(i)
i--
}

32. val rangeInt = 1.rangeTo(10)
=
val rangeInt = 1..10
=
val rangeInt = 1 until 10
dari bawah
ke atas
rangeTo vs downTo
val downInt = 10.downTo(1)
dari atas ke bawah

33. For Loop
Perulangan dengan counter otomatis
fun main() {
val ranges = 1..5
for (i in ranges){
println("value is $i!")
}
}
fun main() {
var counter = 1
while (counter <= 5){
println("value is $counter!")
counter++
}
}
=

34. For Each
Perulangan dengan counter otomatis
fun main() {
val ranges = 1..5
ranges.forEach{
println("value is $i!")
}
}
fun main() {
val ranges = 1..5
for (i in ranges){
println("value is $i!")
}
}
=

35. Break & Continue
Contoh program deteksi angka ganjil sampai angka 10
fun main() {
val listNumber = 1.rangeTo(50)
for (number in listNumber) {
if (number % 2 == 0) continue
if (number > 10) break
println("$number adalah bilangan ganjil")
}
}
* % adalah modulus / sisa pembagian
misal 10 % 2 == 0, 11 % 2 = 1 , 9 % 6 = 3
/*
output:
1 adalah bilangan ganjil
3 adalah bilangan ganjil
5 adalah bilangan ganjil
7 adalah bilangan ganjil
9 adalah bilangan ganjil
*/

36. Lanjutkan Latihan
&
Terus Belajar!

37. OUR LIFE SHOULD BE JUST LIKE
MODULUS. DOESN’T MATTER WHAT VALUE
IS ENTERED, IT’S RESULT ALWAYS
POSITIVE. AND SO SHOULD BE OUR LIFE
IN EVERY SITUATION
- Pranay Neve
’’
’’

38. You can find me at:
● Google : Ahmad Arif Faizin
● Discord : @arifaizin
Thanks!
Any questions?