Variables in Kotlin

In this tutorial, we will learn about variables in Kotlin. We will cover the basics of declaring and using variables, including naming conventions.

What are Variables

Variables in Kotlin are used to store data values that can be manipulated during program execution. They are statically typed, meaning the data type of a variable is known at compile time.

Naming Variables

When naming variables in Kotlin, follow these conventions:

  • Start with a letter or an underscore (_).
  • Subsequent characters can include letters, digits, and underscores.
  • Avoid using reserved keywords as variable names.
  • Use camelCase naming convention for readability.

Syntax

The syntax to declare variables in Kotlin is:

val variableName: DataType = value
var variableName: DataType = value

Example 1: Variable storing Integer Value

  1. Declare an integer variable named num using val.
  2. Assign a value of 10 to the variable.
  3. Print the value of the variable.

Kotlin Program

fun main() {
    val num: Int = 10
    println("The value of num is: $num")
}

Output

The value of num is: 10

Example 2: Variable storing String Value

  1. Declare a string variable named name using var.
  2. Assign the value 'John' to the variable.
  3. Print the value of the variable.

Kotlin Program

fun main() {
    var name: String = "John"
    println("The value of name is: $name")
}

Output

The value of name is: John

Example 3: Variable storing Boolean Value

  1. Declare a boolean variable named isTrue using val.
  2. Assign the value true to the variable.
  3. Print the value of the variable.

Kotlin Program

fun main() {
    val isTrue: Boolean = true
    println("The value of isTrue is: $isTrue")
}

Output

The value of isTrue is: true