Kotlin programming language: Basic introduction to learn now

In the current trends of modern mobile app development, the things that help Kotlin in standing out from other languages is its safety, tool support, and interoperability. You can say that Kotlin is a concise version of Java and is a lot more streamlined to work with. JetBrains has also claimed that Kotlin works equally well with iOS applications as it does with the Android applications. Today in this article, we will give you basic introduction of Kotlin programming language.

What is Kotlin programming language and where is it used?

Kotlin is a cross-platform, statically typed and general-purpose programming language.

kotlin programming language

Cross-platform: It means that the system or the product can work across multiple platforms or operating system environments. For example Microsoft Excel, Word, Powerpoint works on both Windows and Macintosh Operating systems.

Statically typed: Statically typed means that the variables used in the program must explicitly be declared along with their types (data type). For example, C, Java, Kotlin and many more are statically typed. Consider the below C programming code for statically typed programming.

General Purpose programming: As the name suggests it is broadly applicable across all the domains. For example, Java, Python, C, C++ and many more are all general-purpose programming languages.

Why should you choose Kotlin proramming languge?

  • Kotlin programming language provides a mature environment. When compared to other languages, Kotlin was released after going through a number of revisions and so you will hardly face any issues while working with Kotlin. 
  • It was developed keeping an easy transition from Java in mind. Any Java developer can easily understand the code written in Kotlin. The only thing a developer needs to learn is to understand the concepts that Java lacks and Kotlin offers. 
  • Kotlin programming language offers an easy setup feature and does not require any additional plugin. Android Studio 3.0 comes with an in-built feature that says, “ Support Kotlin Development”. 
  • Kotlin is an open-source language that allows core product development and takes relatively less time to convert Kotlin code to Java.
  • With Kotlin, you can seamlessly integrate with Android Studio and set up any project ready to work in less than 10 minutes. 
  • Reduce the boilerplate code that you require frequently and save your time. So, code less, debug less, and thus save time and space.
  • Kotlin enhances performance by increasing the execution speed of the functions compared to Java programming language.

By now you might have understood that Kotlin is a programming language. It is relatively easy to learn and develop applications with it. Provided that it is highly interoperable with Java, this can be a good option for the Java developers.

Highlight features of Kotlin programming language

Concise code

This feature makes Kotlin one of the favourite languages of developers. Clean and concise code leads to a significant decrease in time for coding, reading and maintaining the code. When compared to Java, Kotlin requires approximately 40% fewer lines of code. Thus, increasing the development speed of your application.

Single & comprehensive type system of Kolin programming language

The Kotlin types system is quite simple making it more preferable. It offers some amazing features such as type inference, null support, universal guard and more. Kotlin’s complete type system is organized by two types: supertype and subtype. Supertype represents all non-nullable types called Any. And Subtype represents any type without any instance called Nothing.

Null safety of Kotlin programming language

To boost data consistency, Kotlin comes with an inbuilt Null safety feature that provides security to the codes from data classes. Java has no solution to offer for NullPointerException, the application developers have to figure out on their own. While Kotlin programming language makes sure that any type does not have a value of null. Due to the NullPointerException of Java, more than 70% of the application crashes and Kotlin can save you from these crashes. 

Expressive code

Kotlin is a really simple and understandable language, even a person who has never coded in Kotlin can understand the code. All the functions, data types and other elements are designed in a way that can be interpreted easily and used in the desired way. Thus, Kotlin programming language is said to have expressive code to make things easier for the developers. 

Immutability

Immutability is one of the most magical features of Kotlin. It does not allow any object or its variation to undergo any change after they are created. If you wish to make any changes in the case properties after the creation of the object, then you need to make a clone of the object or whichever variable you are wishing to change. Kotlin makes sure that there are no concurrency or synchronization issues due to immutability.

Modern features

Kotlin is ascended from around six different languages and being a fourth-generation language, Kotlin has a number of modern function that can make your programming as swift as possible. Apart from inheriting the exciting feature from the six languages, Kotlin programming language has also introduced features such as null safety, Lambda function, operator overloading, and more. All these functions can increase your productivity in leaps and bounds. 

Interoperability with Java

You can easily call Kotlin code from Java and Java code from Kotlin. You can even use an automated Java to Kotlin converter that will simplify the migration process and make the development process faster. Interoperability with Java can work for you in a number of especially when it comes to Android application development. You can save the original Java code files and make changes in the new Kotlin file to create new features. 

Begin to do Kotlin Programming Language

Below listed are some of the main concepts that are required for you to understand to get you started.

1. Main function

In Kotlin just as other programming languages, main function is a must. That is where the compiler starts to compile the program. In Kotlin the main function can be written as follows:

fun main() {
println("Hello Kotlin") //Printing "Hello Kotlin"
}
Kotlin programming language

I included a print statement inside the main function to make it more understandable. On executing the main function I got “Hello Kotlin” as the output.

2. Variable declaration

In Kotlin variables can be declared using two keywords namely val and var.

val: It is used for variables whose value never changes. 
var: It is used for variable whose value can change.

In val you cannot reassign the value whereas in var you can reassign the value.

The syntax for declaring the variables in Kotlin programming language are:
keyword variable_name: data_type = value

a. Below is the code snipped for keyword val declaration

val number: Int = 10

fun main() {
println(number) // 10
}
Kotlin programming language

Also when I try to reassign the variable value I will get an error indicating variable value cannot be reassigned because I using val keyword.

val number: Int = 10

fun main() {
number = 20
println(number) // Error
}
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b. Below is the code snipped for keyword var declaration

var number: Int = 10

fun main() {

println(number) // 10
}
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Also when I try to reassign the variable value I will not get an error this time because variable values can be reassigned because I using var keyword.

var number: Int = 10

fun main() {
number = 20
println(number) //20
}
Kotlin programming language
Kotlin programming language

In the same way, you can declare Strings, Boolean, Float, and many more data types.

In general, var is called read-write reference and val is called a read-only reference. We will not be able to reassign the value but we can modify the properties.

fun main() {
val list = mutableListOf<Sring>("a", "b", "c", "d")
println(list)
list = mutableListOf("d", "e)" // Error

list.remove("a")
println(list)
}
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Type Inference

Type inference refers to automatically detect the data type of the variable during the compilation time. In Kotlin the type is defined after variable name:

var title: String

For example, if you assign a type for a variable then you cannot reassign a different type for the same variable by doing so you will get an error:

fun main() {
var name: String = "Tanu"
name= 12
println(name) // Error
}
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However, using the keyword “Any” you can assign an Int to a String or vice-versa as follows:

fun main() {
var name: Any = "Tanu"
name = 12
println(name) //12
}
Kotlin programming language

3. Null Safety

Kotlin programming language variables cannot hold null variables by default so in order to hold null variables you have to use a different syntax as shown below, all you have to do is you have to add a “?” in front of the variable declaration.

var number: Int? = nullfun main() {

println(number) // null
}
Kotlin programming language

In case if you fail to do so, you will get an error saying “Null can not be a value of non-null type int”.

4. Conditional Statements

Like many programming languages Kotlin also has several conditional statement mechanisms. The most common conditional statements are if-else statements. If the condition is true then the if part gets executed and if the condition is false then the else part gets executed.

var num: Int = 10

fun main() {

if(num == 10)
{
num = num + 10
println(num) //20
}

else
{
num = 10
println(num)
}

}
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You can also use multiple if-else and else if statements together as shown below:

var num: Int = 30

fun main() {

if(num == 10)
{
num = num + 10
println(num)
}

else if (num >= 10)
{
num = num + 20
println(num) //50
} else if(num >= 20)
{
num = num + 30
println(num)
} else
{
print(num)
}
}
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In kotlin programming language you can also use a when expression to replace multiple if-else as see below:

val number: Int = 100
val answer = when {
number == 42 -> "Best"
number > 35 -> "Good"
else -> "Worst"
}

fun main() {
println(answer) //Good
}
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5. Functions

Functions are a block of organized and reusable code that is used to perform a single task. In Kotlin in order to create a function you have to use the fun keyword, and next defining the data types of input that the function takes. Then finally you have to return the output of the function. The syntax of the function is as shown below:

fun function_name(): data_type{
statement 1
statement 2
-
-
-
statement nreturn function_name
}

The statement 1, 2 and n are just executable statements or also called the body of the function which must be placed within the function. Consider an example:

fun add_two_numbers(): Int{
val num1: Int = 10
val num2: Int = 20
val num3: Int = num1 + num2

return num3
}

fun main() {
println(add_two_numbers())
}
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Function taking two parameters as input

In this case all you have to do pass two parameters or arguments to the function and then declare their types, and then you can call the function by passing the values as inputs:

fun add_two_numbers(num1: Int, num2: Int ): Int{

val num3: Int = num1 + num2

return num3
}

fun main() {
println(add_two_numbers(10, 20)) // 30
}
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Kotlin programming language

6. Classes and its properties

In Kotlin programming language in order to declare a class you need to use the keyword class and then its properties. The syntax of the class and its properties are as shown below:

class class_name{    properties of a class}

Classes represent state using properties. A property is a class-level variable that can include a getter, a setter, and a backing field. An object is an instance of a class, with the help of an object we can access the variables of the class. For example:

class dog {
var name: String = "Danny"
var breed: String = "Boxer"
var color: String = "White"
}

fun main() {
var d = dog()
println(d.name) //Danny
println(d.breed) //Boxer
println(d.color) //White
}
Kotlin programming language

7. Getting the input from the user of Kotlin Programming Language

In order to get the input from the user, Kotlin provides a special method called readline which reads the line entered by the user. For example:

fun main() {
var name: String? = null
println("Enter your name")

name = readLine()
println("Your name is: $name") // Tanu Nanda Prabhu
}
Kotlin programming language

The above are some basic and important concepts of Kotlin programming language that you need to know. However, this is not the end of Kotlin, this is just the beginning. I will try to upload more tutorials about Kotlin Programming and help you guys in mastering the language. For more details about Kotlin, I recommend you to go through the official Kotlin documentation, and try to understand furthermore.

To Sum Up with Kotlin Programming Language

With its increasing popularity. Kotlin has its latest versions equipped with all the features required for Android application development. The latest version of Kotlin was released on 23rd March and is rigged with exciting features.

Quickly get your requirements together and approach an expert Kotlin application development company for an all-equipped mobile application.

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