1 - variables principales

fun main() {
    var prueba = "holita"
    println(prueba)

    prueba = "adios" // to reasign a new variable, not necessary to write "var" again.
    println(prueba)

    prueba = ""
    println(prueba)
    println(prueba.isEmpty()) // if var. is empty => true

    var age: Int = 30 // var var_name: "x" -> x = the type of the variable: int, float, string, etc...
    age = 32
    println(age)

    val nombre = "edgar" // val => variable cant be changed. VAR is a read-only var.
    println(nombre)
    // nombre = "fiorella" ||| will cause error cuz the variable is "val" type

    println(age::class)

    var lower_number_type: Byte = 8 // 8-bit signed int. "Byte" must be written with the first letter in capital form
    var my_short: Short = 16 // 16-bit signed int. idem
    var most_popular_number_type: Int = 32 //. idem
    var huge_number: Long = 64 //. idem
    var decimal_value: Float = 32.00F // 32-bit floating type number.    idem
    var larger_decimal: Double = 64.00
    // this value all are object, that means we can call method and properties on them.    idem
    println(my_short.toDouble()::class)

    var bigLong: Long = 1_000_000 // for easy reading of big numbers
    println(bigLong)

    var newVar = age.plus(1) // or "age.plus(bigLong)"  |||(age=32), its for adding diferente types of variables
    println(newVar)

    var nombre2: String = "Juanito"//we can call dif method and properties on variables
    println(nombre2.length)
    println(nombre2.decapitalize())

    var eg1: String = "holi boli" // "" is for String
    var eg2: Char = 'a'           // '' is for char || in kotlin, Char represent 16-bit Unicode character
    println(eg2)

    var frase: String = """
    hello
    welcome to the jungle
    yeah
    """.trimIndent() // trinIndent, eliminate the indentation
    println(frase)

    var variable1: String = "mundo"
    var primer_nombre: String = "javier"
    // $ -> es para concatenar String, tambien dentro de {} se puede poner metodos.
    println("hola $variable1, tu nombre es $primer_nombre y tiene ${primer_nombre.length} caracteres")

    // boolean variables
    var isempty: Boolean = false
    println(isempty)
    println(isempty.not()) // you can negate a variable in boolean

    isempty = "".isBlank() // ".isBlank()" -> a fun that check is the length is 0, if it is then give "true" if not
                            // then if give a "false" answer
    println(isempty)
    isempty = "javier".isBlank()
    println(isempty)
    // boolean ends


}