📌 Variables in Kotlin

In Kotlin, variables are used to store data. Kotlin provides two types of variables:

1. Immutable (Read-only) → val

2. Mutable (Changeable) → var

✅ 1. Immutable Variables (val)

• Declared using the val keyword.

• Value cannot be changed after assignment.

• Similar to final in Java.

📌 Example:

kotlin
 name = "Vikash"val age = 30println("Name: $name, Age: ")

• name and age cannot be reassigned.

✅ 2. Mutable Variables (var)

• Declared using the var keyword.

• Value can be changed or reassigned.

📌 Example:

kotlin
var count = 10println("Initial Count: $count")count = println("Updated Count: $count")

✅ Variable Declaration with Data Types

In Kotlin, you can explicitly declare the data type using : Type.

✅ Type Inference in Kotlin

Kotlin supports type inference, meaning it can automatically detect the data type based on the assigned value.

📌 Example:

kotlin
 language = "Kotlin"// Type inferred as Stringvar year = 2025// Type inferred as Int

✅ Nullable Variables

In Kotlin, variables are non-nullable by default. If you need a variable to hold a null value, you must use ?.

📌 Example:

kotlin
var name: String? = nullprintln("Name: $name") lateinitvar greeting: Stringfun() {    greeting = "Hello, Kotlin!"    println(greeting)}

✅ Constant Variables in Kotlin

If you need constants (values that won't change), use const val.

• const val is a compile-time constant and should be initialized with a value directly.

📌 Example:

kotlin
constval PI = 3.14159println("Value of PI: $PI")

✅ Conclusion

• Use val for immutable variables (read-only).

• Use var for mutable variables (modifiable).

• Use lateinit for deferred initialization.

• Use ? for nullable variables.

• Use const val for constants.