Kotlin Complete Guide 📱

1. What is Kotlin?

Kotlin is a modern programming language used for Android app development, officially supported by Google.

2. First Program

fun main() {
    println("Hello Kotlin")
}

3. Variables

val name = "Sasank"
var age = 18

4. Data Types

Int, String, Double, Boolean

5. If-Else

val age = 18

if(age >= 18){
    println("Adult")
}else{
    println("Minor")
}

6. Loops

for(i in 1..5){
    println(i)
}

7. Functions

fun add(a: Int, b: Int): Int {
    return a + b
}

8. OOP in Kotlin

class Car(val model: String) {
    fun drive(){
        println("Car is running")
    }
}

9. Android MainActivity

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
    }
}

10. Button Click

button.setOnClickListener {
    textView.text = "Clicked!"
}

11. Mini Project Ideas

• To-Do App 📋
• Calculator App 🧮
• Login Screen 🔐
• Weather App 🌦️