Exercise for strings in Kotlin

StringExercise.kt

var str: String = "Hello World!" //With type specification
var str1 = "Get started with Kotlin strings" //With out type specification
var str2 = str + ", "
var emptyString = String()//Creating an empty string
fun main(args: Array<String>) {
    str2 += str1
    println(str) //Result: Hello World!
    println(str1) //Result: Get started with Kotlin strings
    println(str2) //Result: Hello World!, Get started with Kotlin strings
    
    //String Manipulation
    //Length of the string
    println("Length of str2: " + str2.length) //Result: Length of str2: 45
    println("Character at the index 10 of the string: " + str2.get(10)) //Result: Character at the index 10 of the string: d

    println("Substring from str1: " + str1.subSequence(16,23)) //Result: Substring from str1:  Kotlin

    //String comparison
    var strCompare = "Hello WORLD!"
    println(strCompare.compareTo(str)) //Result: -32
    //Using ignoreCase parameter
    println(strCompare.compareTo(str, true)) //Result: 0
    
    //Accessing characters in a string
    //Using index operator
    println("Index operator: Character at 5th position: " + str[4]) //Result: Index operator: Character at 5th position: o
    //Using get method
    println("Get method: Character at 5th position: " + str.get(4)) //Result: Get method: Character at 5th position: o
    
    //String iteration
    for(element in str) {
        println(element)
    }
    
    //String templates
    var len = str1.length
    //Inserting a variable
    println("Length of str1 is $len") //Result: Length of str1 is 31
    //Inserting an expression
    println("Length of str1 is ${str1.length}") //Result: Length of str1 is 31
    
    //To use the $ symbol in a string we need to escape the character
    var escapedDollar = "Balance is \$45"
    println(escapedDollar) //Result: Balance is $45

    //Raw strings => These are placed inside triple quotes. We don't have to escape characters here.
    //Used in multilines without concatenation. It is handy while specifying file/directory path
    
    var rawString = """Hi Kotlin
            Where to find your tutorials?
            I'm eager to learn you.\n"""
    println(rawString) 
    //Result: Hi Kotlin
    //        Where to find your tutorials?
    //        I'm eager to learn you.\n
    //trimMargin() to remove the whitespacing.
    rawString = """Hi Kotlin
            |Where to find your tutorials?
            |I'm eager to learn you.\n""".trimMargin("|")
    println(rawString)
    //Result: Hi Kotlin
//Where to find your tutorials?
//I'm eager to learn you.\n
    
    //String templates and raw strings
    var strTemplate = "Hi Kotlin, "
    var rawStr = """$strTemplate
        |Your balance is $60.00""".trimMargin("|")
    println(rawStr)
    //Result: Hi Kotlin, 
//Your balance is $60.00
    
    //Overriding String method
    
    class Person(var name: String, var age: Int) {
        override fun toString(): String {
            return "Person name is $name and age is $age"
        }
    }
    
    var person = Person("Madhan", 25)
    println(person) // Result: Person name is Madhan and age is 25
    
    //String equality
    //Two types
    //Referential equality(===): Checks the references are same.
    //Structural equality(==): Checks the contents are equal
    
    var s1 = "Kotlin"
    var s2 = "How are you"
    var s3 = "Kotlin"
    var s4 = "Kot"
    var s5 = "lin"
    var s6 = s4 + s5
    
    println(s1===s2) // Result: false, s1 and s2 points to different strings
    println(s1===s3) // Result: true, s1 and s2 points to the same string in the StringPool
    println(s1==s3) // Result: true, since contents are equal
    println(s1==s2) // Result: false, since contents are not equal
    println(s1==s6) // Result: true, since the contents are equal
    println(s3==s6) // Result: true, since the contents are equal
    println(s1===s6) // Result: false, since s6 is made up of two different strings. Therefore, s1 and s6 points to different strings    
}