Initial Commit

.gitignore

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+.idea
+*.iml

Readme.md

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+## Kotlin Tutorials
+
+### Kotlin Basics
+
+* [Overview and Setup](https://www.callicoder.com/categories/kotlin/)
+
+* [Writing your first Kotlin Program](https://www.callicoder.com/kotlin-introduction-hello-world/)
+
+* [Variables and Data Types](https://www.callicoder.com/kotlin-variables-data-types/)
+
+* [Kotlin Operators](https://www.callicoder.com/kotlin-operators/)
+
+* [Kotlin Control Flow: if and when expressions, for and while loops](https://www.callicoder.com/kotlin-control-flow/)
+
+* [Nullable Types and Null Safety in Kotlin](https://www.callicoder.com/kotlin-nullable-types-null-safety/)
+
+
+### Kotlin Functions
+
+* [Kotlin Functions, Default and Named Arguments, Varargs and Function Scopes](https://www.callicoder.com/kotlin-functions/)
+
+* [Kotlin Infix Notation - Make function calls more intuitive](https://www.callicoder.com/kotlin-infix-notation/)
+
+
+### Kotlin OOP
+
+* [Classes, Objects, Constructors and Initializers](https://www.callicoder.com/kotlin-classes-objects-constructors-initializers/)
+
+* [Properties, Backing Fields, Getters and Setters](https://www.callicoder.com/kotlin-properties-backing-fields-getters-setters/)
+
+* [Kotlin Inheritance, Overriding Methods, and Properties](https://www.callicoder.com/kotlin-inheritance/)
+
+* [Kotlin Abstract Classes](https://www.callicoder.com/kotlin-abstract-classes/)
+
+* [Introduction to Data Classes in Kotlin](https://www.callicoder.com/kotlin-data-classes/)
+
+* [Kotlin Type Checks and Smart Casts](https://www.callicoder.com/kotlin-type-checks-smart-casts/)

src/t1_hello_world/Hello.kt

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+package t1_hello_world
+
+// Kotlin Hello World Program
+fun main(args: Array<String>) {
+    println("Hello, World!")
+}

src/t2_variables/Variables.kt

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+package t2_variables
+
+fun main(args: Array<String>) {
+
+    /*
+        Declaring Variables
+     */
+
+    // Immutable variable (val)
+    val name = "Bill Gates"
+    // name = "Satoshi Nakamoto"	Error: Val cannot be reassigned
+
+    // Mutable variable (var)
+    var country = "USA"
+    country = "India"    // Works
+
+    println("$name, $country")
+
+
+
+    //===========================
+
+    /*
+      Type inference
+    */
+
+    val greeting = "Hello, World"  // type inferred as `String`
+    val year = 2018                // type inferred as `Int`
+
+
+    // Explicitly defining the type of variables
+    val myStr: String = "Hello"
+    val myInt: Int = 20
+
+
+    // Type declaration is mandatory here, since the variable is not initialized at the time of declaration
+    var language: String
+    language =  "French"
+
+    println("$greeting $year $myStr $myInt $language")
+}

src/t3_basic_types/Arrays.kt

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+package t3_basic_types
+
+fun main(args: Array<String>) {
+
+    // Creating Arrays
+    var numbers = arrayOf(1, 2, 3, 4, 5)
+    var animals = arrayOf("Cat", "Dog", "Lion", "Tiger")
+
+    var mixedArray = arrayOf(1, true, 3, "Hello", 'A')	// Works and creates an array of Objects
+
+    var numArray = arrayOf<Int>(1, 2, 3, 4)  // Enforcing Type
+
+
+
+    // Array Indexing
+    val myDoubleArray = arrayOf(4.0, 6.9, 1.7, 12.3, 5.4)
+    val firstElement = myDoubleArray[0]
+    val lastElement = myDoubleArray[myDoubleArray.size - 1]
+
+
+
+    // Primitive Arrays
+    val myCharArray = charArrayOf('K', 'O', 'T')  // CharArray (corresponds to Java 'char[]')
+    val myIntArray = intArrayOf(1, 3, 5, 7)		// IntArray (corresponds to Java 'int[]')
+
+
+
+    // Creating Arrays using Array() constructor
+    var mySquareArray = Array(5, {i -> i * i})	// [0, 1, 4, 9, 16]
+}

src/t3_basic_types/NumericTypes.kt

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+package t3_basic_types
+
+fun main(args: Array<String>) {
+    // Kotlin Numeric Types Examples
+    val myByte: Byte = 10
+    val myShort: Short = 125
+
+    val myInt = 1000
+    val myLong = 1000L	// The suffix 'L' is used to specify a long value
+
+    val myFloat = 126.78f   // The suffix 'f' or 'F' represents a Float
+    val myDouble = 325.49
+
+    // Use underscores to make numeric values more readable
+    val hundredThousand = 100_000
+    val oneMillion = 1_000_000
+
+    val myHexa = 0x0A0F  // Hexadecimal values are prefixed with '0x' or '0X'
+    val myBinary = 0b1010  // Binary values are prefixed with '0b' or '0B'
+
+    println("$myByte $myShort $myInt $myLong $myFloat $myDouble $hundredThousand $oneMillion $myHexa $myBinary")
+}

src/t3_basic_types/Strings.kt

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+package t3_basic_types
+
+fun main(args: Array<String>) {
+    // Delcaring a String
+    var myStr = "Hello World"
+
+
+    // String Indexing
+    var name = "John"
+    var firstCharInName = name[0]  // 'J'
+    var lastCharInName = name[name.length - 1]  // 'n'
+
+
+    // Escaped and Raw String
+    var myEscapedString = "Hello Reader,\nWelcome to my Blog"
+
+    var myMultilineRawString = """
+    The Quick Brown Fox
+    Jumped Over a Lazy Dog.
+    """
+
+    println("$name, $firstCharInName, $lastCharInName, $myEscapedString, $myMultilineRawString")
+}

src/t3_basic_types/TypeConversions.kt

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+package t3_basic_types
+
+fun main(args: Array<String>) {
+    val myInt = 100
+    val myLong = myInt.toLong()   // Explicitly converting 'Int' to 'Long'
+
+    val doubleValue = 176.80
+    val intValue = doubleValue.toInt()  // 176
+
+    val anotherInt = 1000
+    anotherInt.toString()  // "1000"
+
+    val str = "1000"
+    val intValueofStr = str.toInt()
+}

src/t4_operators/NumericOperations.kt

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+package t4_operators
+
+fun main(args: Array<String>) {
+    var a = 10
+    var b = 20
+    var c = ((a + b) * ( a + b))/2   // 450
+
+    var isALessThanB = a < b   // true
+
+    a++     // a now becomes 11
+    b += 5  // b equals to 25 now
+
+
+    // =======================
+
+
+    // Operators are internally converted to method calls
+    var x = 4
+    var y = 5
+
+    println(x + y)
+
+    // equivalent to
+    println(x.plus(y))
+
+
+    // ======================
+
+
+    // Bitwise Operators
+    1 shl 2   // Equivalent to 1.shl(2), Result = 4
+    16 shr 2  // Result = 4
+    2 and 4   // Result = 0
+    2 or 3    // Result = 3
+    4 xor 5   // Result = 1
+    4.inv()   // Result = -5
+
+
+}

src/t4_operators/StringOperations.kt

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+package t4_operators
+
+fun main(args: Array<String>) {
+    // String Concatenation
+    var firstName = "Rajeev"
+    var lastName = "Singh"
+    var fullName = firstName + " " + lastName	// "Rajeev Singh"
+
+    // String Interpolation
+    var a = 12
+    var b = 18
+    println("Avg of $a and $b is equal to ${ (a + b)/2 }")
+}

src/t5_conditionals/IfElse.kt

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+package t5_conditionals
+
+fun main(args: Array<String>) {
+    // If Statement
+    var n = 34
+    if(n % 2 == 0) {
+        println("$n is even")
+    }
+
+    // The curly braces are optional if the body of if statement contains a single line
+    if(n % 2 == 0) println("$n is even")
+
+
+    // =======================
+
+
+    // If-Else Statement
+
+    var a = 32
+    var b = 55
+
+    if(a > b) {
+        println("max($a, $b) = $a")
+    } else {
+        println("max($a, $b) = $b")
+    }
+
+    // =======================
+
+    // Using If as an expression
+    var max = if(a > b) a else b
+    println("max($a, $b) = $max")
+
+
+    // If-Else branches with block bodies
+    max = if(a > b) {
+        println("$a is greater than $b")
+        a
+    } else {
+        println("$a is less than or equal to $b")
+        b
+    }
+    println("max($a, $b) = $max")
+
+
+    // ========================
+
+    // If Else If Chain
+    var age = 17
+    if(age < 12) {
+        println("Child")
+    } else if (age in 12..17) {
+        println("Teen")
+    } else if (age in 18..21) {
+        println("Young Adult")
+    } else if (age in 22..30) {
+        println("Adult")
+    } else if (age in 30..50) {
+        println("Middle Aged")
+    } else {
+        println("Old")
+    }
+
+}