Kotlin Data Types:
Kotlin has the following basic data types: Boolean Char Byte Short Int Long Float Double Array
Kotlin Boolean values In Kotlin the boolean data type is a primitive data type having one of two values: true or false.
Example:
fun main() {
var name = ""
val male: Boolean = Random.nextBoolean()
if (male) {
name = "Robert"
}
if (!male) {
name = "Victoria"
}
println("We will use name $name")
println(9 > 8)
} Kotlin integers: Integers are a subset of the real numbers. They are written without a fraction or a decimal component. Integers fall within a set Z = {..., -2, -1, 0, 1, 2, } Integers are infinite.
The usage of integers depends on the type of the task we have. All variables initialized with integer values not exceeding the maximum value of Int have the inferred type Int. If the initial value exceeds this value, then the type is Long. To specify the Long value explicitly, append the suffix L to the value. When we work with integers, we deal with discrete items. Kotlin integer min/max values: The integer data types provide their min and max values as constants.
Kotlin BigInteger: Byte, Short, Int and Long types are used to represent fixed precision numbers. This means that they can represent a limited amount of integers.
We print the largest integer value which can be represented by the Long type. Example: val b = BigInteger("92233720368547758071") val c = BigInteger("52498235605326345645")
We define two BigInteger objects. They both hold larger values that a Long type can hold. val a = b.multiply(c)
Kotlin arithmetic overflow: An arithmetic overflow is a condition that occurs when a calculation produces a result that is greater in magnitude than that which a given register or storage location can store or represent. When we try to assign a value beyond the range of a data type. This leads to an arithmetic overflow. When an overflow occurs, the variable is reset to a negative upper range value. Example: fun main() {
var a: Byte = 126
println(a)
a++
println(a)
a++
println(a)
a++
println(a)
}
Kotlin floating point numbers: Real numbers measure continuous quantities, like weight, height, or speed. Floating point numbers represent an approximation of real numbers in computing. In Kotlin we have two primitive floating point types: Float and Double. The Float is a single precision type which stores numbers in 32 bits. The Double is a double precision type which stores numbers in 64 bits. Example: fun main() {
val speed: Float
val distance = 0.1f
val time: Float = 9.87f / 3600
speed = distance / time
println("The average speed of a sprinter is $speed km/h")
}
We use the DecimalFormat class to arrange our double value into standard decimal format. val bd = BigDecimal("1.212e-19")
println(bd.toEngineeringString()) println(bd.toPlainString())
Kotlin explicit conversions: Kotlin supports explicit conversion between numbers. Every number type has the following conversion functions: toByte(): Byte toShort(): Short toInt(): Int toLong(): Long toFloat(): Float toDouble(): Double toChar(): Char Kotlin strings and chars: A String is a data type representing textual data in computer programs. A string in Kotlin is a sequence of characters. A Char is a single character. Strings are enclosed by double quotes.
Kotlin Arrays: Array is a complex data type which handles a collection of elements. Each of the elements can be accessed by an index. All the elements of an array must be of the same data type.
Single line Expressions in Kotlin;
How to use function arguments in Kotlin: It is used by passing in the parameters in between the parantheses. Arguments are passed by value; that is, when a function is called, the parameter receives a copy of the argument's value, not its address. This rule applies to all scalar values, structures, and unions passed as arguments. Modifying a parameter does not modify the corresponding argument passed by the function call.
How to use named parameters in kotlin functions. We use the name of the parameters, this is to make the code readable on other IDE's like visual studio.
How to use default argument values in Kotlin. By providing default argument we avoid repetition, we do so by specifying the default value for an argument.This cleans up the code such that we only see the relevant code.
Function refactoring to new lines and named arguments in intelliJ. This saves us time and makes the code more readble.
How to provide multiple arguments of the same type with vararg. vararg means variable argument. we write the values in plural.
How to create a class in Kotlin class is a reusable template.
Primary class constructors in kotlin. We add constructor after class. We set default values inside primary constructors.
How to use multiple constructors in a kotlin class. We can have a secondary constructor inside another class constructor and we use the constructor keyword.
How to use the kotlin init block. It is called after the primary constructor.
How to use class properties.
How to use multiple properties in a kotlin class
How to create a function inside a kotlin class.
Kotlin companion objects. We use the companion object keyword. we use foreach to have a nice looking output; it uses it by default.
How to create a singleton in Kotlin. WE create the singleton by replacing the class word with objects. We can put methods inside of here as well.
How to declare constants in kotlin
How to use the kotlin lateinit modifier; this is basically used to indicate that you are going to initialize that particular property later. It must be used with a var because we're allowed to use it only on mutable properties.
Kotlin Nested Class; kotlin allows us to create a class inside another class.
Kotlin innerclass; for the nested class to have access to a variable we use inner class keyword.
How to create an enum in Kotlin.
How to use kotlin when expression.
Exhaustive and non-exhaustive when expression in kotlin