Number Data type Usage and Type Conversion in Kotlin

Definition

• There are 6 built-in types of numbers in Kotlin. They are
  • Double
  • Float
  • Long
  • Int
  • Short
  • Byte
• Double and Float are floating point numbers.
• The type can be either declared explicitly or the compiler itself has the ability to infer the type of the assigned value.

Syntax and declaration

Thus a Number can be declared by 3 ways as mentioned below.

1. Mentioning type explicitly

val variable_name : Number = value

for example,

val number : Number = 100f

2. Number type is automatically inferred

val variable_name = value

for example,
//Number type is automatically inferred
val number = 100

3. Declaring and Initializing separately

var variable_name : Number 
variable_name = value

for example

//Declaring and Initializing separately
var number:Number 
number = 100.57

Number Datatype Example Program in Kotlin

// Number Datatype Kotlin example program
// Data type Kotlin Programs, Basic Kotlin Programs

fun main(args:Array<String>) {
    //Assigning value to Number variable explicitly and is automatically cast to Float Number
    val a:Number = 22.8f
    //Assigned value is inferred automatically by compiler and is automatically cast to Float Number
    val b = 100.0f

    println("Value of a is $a")
    println("Value of b is $b")
}

Sample Output

Value of a is 22.8
Value of b is 100.0

Type conversion syntax and declaration

//Number to Double Conversion 
val variable_name = number_variable.toDouble()

//Number to Int Conversion 
val variable_name = number_variable.toInt()

Number type Conversion Example Program in Kotlin

// Number Datatype Kotlin example program
// Data type Kotlin Programs, Basic Kotlin Programs

fun main(args: Array < String > ) {
	val number : Number = 100.2
	//Conversion to Float
    val num1: Float = number.toFloat()
    //Conversion to Int
    val num2: Int = number.toInt()
	//Conversion to Double
    val num3: Double = number.toDouble()
    //Conversion to Byte
    val num4: Byte = number.toByte()

    //Print values after conversion
    println("Number to Float : number Value : $num1")
    println("Number to Int : number Value : $num2")
    println("Number to Double : number Value : $num3")
    println("Number to Byte : number Value : $num4")
}

Sample Output

Number to Float : number Value : 100.2
Number to Int : number Value : 100
Number to Double : number Value : 100.2
Number to Byte : number Value : 100

How It Works

This Kotlin program demonstrates Number Data type Usage and Type Conversion. It first prepares the data it needs, then performs the core operation step by step, and finally prints the output shown in the Sample Output above.

1. Declare the variables that hold the program’s data.
2. Print the final result to the console so you can compare it with the sample output.

Try changing the input values and re-running the program to see how the output changes — this is the fastest way to understand how the logic behaves.