Kotlin is a statically-typed programming language introduced by JetBrains in 2016, known for its conciseness and interoperability with Java, and is now the preferred language for Android development. The document covers key concepts such as variable types (mutable and immutable), string templates, conditional statements (if-else, when), arrays, loops, null safety, ranges, and functions, providing examples for each feature. These fundamentals set the foundation for programming in Kotlin, emphasizing its modern approach and ease of use.

2. What’s in it for you ?
Introduction to Kotlin
Variables in Kotlin
String templates
Array
Loops in Kotlin
Null safety
Ranges
Kotlin functions
If-else and when

3. Introduction to Kotlin
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2
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Kotlin is a general-purpose, statically-typed programming language
developed and released by Jet Brains in 2016.
Kotlin is concise and more expressive than Java. It is fully
interoperable with Java.
Google also announced Kotlin as the first-class language for
android development

4. Variables in Kotlin
var
val
There are two types of variables in Kotlin
var is the variable whose value
can reassigned (mutable)
var name = “Raj”
name = “Sid“ // Value is reassigned
println(name)
OUTPUT: Sid

5. Variables in Kotlin
var
val
There are two types of variables in Kotlin
val is the variable whose value
cannot be reassigned
(immutable)
val name = “Raj”
name = “Sid”
println(name)
OUTPUT: error (Value can’t be
reassigned)

6. Variables in Kotlin
var
val
There are two types of variables in Kotlin
var name = ”Mickey” // String
val roll = 20 // integer
println(name)
println(roll)
OUTPUT: Mickey
20

7. String templates
The string templates allows us to include the expressions,
variable references inside the string.
The references in a string start with $. We can easily add the
variables in the string instead of concatenating them.
var name1= “Ronny”
var name2= “Mickey”
println(“Both $name1 and $name2 are best friends”)
println(“${name1.toUpperCase()} is older than $name2” )
OUTPUT: Both Ronny and Mickey are best friends
RONNY is older than Mickey

8. If else and when statements
In Kotlin language, the if else statements can also
be used as expressions that means they can return
a value.
While using if-else as an expression, it is
mandatory to use the else branch.
For example:
fun main()
{
val a = 205
val b = 195
val great= if (a > b)
“$a is greater”
else
“$b is greater”
println("$great")
}

9. If else and when statements
In Kotlin language, when statement is similar to
switch statement in Java.
It is used to select one code block out of multiple
code blocks based on a conditional expression.
For example:
val tap = 4
val order = when (tap) {
1 -> “Pizza”
2 -> “Pasta”
3 -> “Fried rice”
4 -> “Wrap”
5 -> “Sandwich”
6 -> “Burger”
else -> ”Invalid”
}
println(order)

10. Array
Arrays are generally used to store multiple values in
a contiguous memory location in a single variable.
In Kotlin you can easily create arrays.
Var names= arrayOf( “Sid”, “Robby”, “Max”, “John”)
For example:
fun main() {
var names= arrayOf( “Sid”, “Robby”,
“Max”, “John”)
for (n in names) {
println(n)
}
}

11. Loops in Kotlin
Loops are generally used while working with arrays.
1) For loop
for (n in numbers) {
println(n)
}
}
Here n is the variable, in is the operator and
numbers is the array name.
For example:
fun main() {
var numbers= arrayOf( 4, 2, 5, 12, 7)
for (n in numbers) {
println(n)
}
}

12. Loops in Kotlin
The while and do-while loop are similar to the loops
in Java.
1) while loop: The while loop checks the condition
and executes through the block of code as long as
the specified condition is true.
2) do-while loop: The do-while loop executes the
do block once before checking if the condition is
true.
For example:
while loop
while(condition)
{
body of the loop
}
do-while loop
do
{
body of the loop
}
while(condition);

13. Null Safety
Null safety is a feature that solves the problem of null pointer
exception.
In Kotlin, you can make a null type variable.
To create a variable or string which can hold a null value, we can
simply define them by putting the question mark “?” in the end.
Example:
var name: String?=null

14. Ranges
Range can be defined as an interval from start to end. The
expressions are created with operator(..).
For example:
for(i in 0..7)
{
println(i)
}
Output: 0 1 2 3 4 5 6 7
For example:
for(i in 0..10 step 2 ) // 0 2 4 6…
{
print(i);
}
for(i in 7 downTo 2 ) // 7 6 5 4…
{
println(i);
}

15. Kotlin Functions
Functions which are also known as methods are the block of
code which runs whenever it is invoked.
It is defined with the keyword fun
Example: fun box()
Function parameters are specified inside the parentheses.
The type of parameter is specified after the name of the
parameter.
For example:
fun box(num1: Int, num2: Int): Int{}
Function
name
Parameters
type
Return
type