Kotlin Learning

Main.kt

import java.util.*

fun main() {
    println("Hello World!")
    // Int variables examples
    var a = 1
    a = 2
    val b = 3
    // b = 4 // Error: b is a constant
    // Constants examples
    val c: Int = 1
    val d: Int = 2
    val e: Int = 3
    val f = 4
    // Print variables
    println(a)
    println(b)
    println(c)
    println(d)
    println(e)
    println(f)
    // Floating point variables examples
    var g = 1.0
    g = 2.0
    val h = 3.0
    // h = 4.0 // Error: h is a constant
    // Constants examples
    val i: Double = 1.0
    val j: Double = 2.0
    val k: Double = 3.0
    // Print variables
    println(g)
    println(h)
    println(i)
    println(j)
    println(k)

    // String examples
    val name = "John"
    val age = 25
    val greeting = "Hello $name, you are $age years old"
    println(greeting)
    // String interpolation
    val greeting2 = "Hello $name, you are $age years old"
    println(greeting2)
    // String concatenation
    val greeting3 = "Hello " + name + ", you are " + age + " years old"
    println(greeting3)
    // String length
    val greeting4 = "Hello $name, you are $age years old"
    println(greeting4.length)
    // String indexing
    val greeting5 = "Hello $name, you are $age years old"
    println(greeting5[0])
    // String slicing
    val greeting6 = "Hello $name, you are $age years old"
    println(greeting6.slice(0..3))
    // String replace
    val greeting7 = "Hello $name, you are $age years old"
    println(greeting7.replace("Hello", "Hi"))
    // String capitalize
    val greeting8 = "hello $name, you are $age years old"
    // println(greeting8.capitalize())
    println(greeting8.replaceFirstChar {
        if (it.isLowerCase())
            it.titlecase(Locale.getDefault())
        else it.toString()
    })
    // String trim
    val greeting9 = " hello $name, you are $age years old "
    println(greeting9.trim())
    // String split
    val greeting10 = "Hello $name, you are $age years old"
    println(greeting10.split(" "))
    // String to upper case
    val greeting11 = "hello $name, you are $age years old"
    println(greeting11.toUpperCase())
    // String to lower case
    val greeting12 = "HELLO $name, you are $age years old"
    println(greeting12.toLowerCase())
    // String to char array
    val greeting13 = "Hello $name, you are $age years old"
    println(greeting13.toCharArray())
    // String to byte array
    val greeting14 = "Hello $name, you are $age years old"
    println(greeting14.toByteArray())
}