Kotlin Variables & Data Types

Learn about variables, constants, and data types in Kotlin.

Variable Declaration

// Mutable variable (can be reassigned)
var count: Int = 10
count = 15  // Valid

// Immutable variable (cannot be reassigned)
val name: String = "Kotlin"
name = "Java"  // Compilation error

// Type inference
val message = "Hello"  // Inferred as String
val pi = 3.14          // Inferred as Double

Basic Data Types

Type	Description	Example
Int	32-bit integer	42, -7
Long	64-bit integer	42L, -7L
Double	64-bit floating point	3.14, -2.71
Float	32-bit floating point	3.14f, -2.71f
Boolean	True or false	true, false
Char	Single character	'A', '\n'
String	Sequence of characters	"Hello", "Kotlin"

Type Conversion

val number: Int = 42
val longNumber: Long = number.toLong()

val stringNum = "123"
val intNum = stringNum.toInt()

String Templates

val name = "Alice"
println("Hello, $name!")  // Hello, Alice!

val a = 10
val b = 20
println("Sum: ${a + b}")  // Sum: 30

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