Day 1

1. Hello.kt


// The Entry point of kotlin program is main function
fun main(){
	println("Hello world")	
}

2. Variable.kt


fun main(){

    // var -> variable [ mutable , reassigned ]
    var a = 10
    // val -> value [immutable , Constant ]
    val b = 480

    // Declare variable with datatype
    // : operator use to set datatype
    // this variable value is null
    var uu : Unit 
		// Default type is Any it Set its value datatype when first assigned
		var aa: Any = "A" 
    var i : Int = 10
    var ii : Float = 25.88F
    var dd : Double = 67.99
    var cc : Char = 'A'
    var r : String = "Devansh"
    var rr : Boolean = false

    // assign value from options
    // if expression is true then if value will be assigned and false than else value will be assigned
    val name = if(a > b) "Haresh" else "Devansh"
    //print(name)

}

3. Conditional.kt


fun main() {
    val name: Boolean = false
    var age = 18
    if (name) {
        println("Nothing")
    } else {
        println("Devansh")
    }

    // if .. else if .. else Ladder
    if (age < 18) {
        println("You are an Child")
    } else if (age >= 18) {
        if (age < 40) {
            println("You are a Adult")
        } else {
            println("You are senior citizen ")
        }
    } else {
        println("Invalid")
    }
}

4. Function.kt


fun main() {


    // No argument, No return value
    whileloop()

    // No argument, return value
    mysinglereturn()

    // With argument, No return value
    forloop(10)

    // With  arguments , With Return value
    myfunction(25, 50)
}


fun whileloop() {
    var i = 1
    while (i <= 10) {
        println("Number $i")
        i++
    }
}

fun mysinglereturn(): Int = 28


fun forloop(end: Int) {

    // until is keyword
    for (i in 0 until end) {
        println(i)
    }

    //  .. is range operator
    for (i in 0..end) {
        println(i)
    }

}


fun myfunction(a: Int, b: Int): Any {
    println("I am function ${a + b}")
    return true
}