Int Data type Usage and Type Conversion in Kotlin

Definition

• Int is a 32-bit number in Kotlin. The type can be either declared explicitly or the compiler itself has the ability to infer the type of the assigned value.
• Int value ranges from -2147483648 to 2147483647 ie., -(2^31) through 0 to (2^31)-1
• In JVM, the characteristics of this “Int” variable is derived from the characteristics of primitive type int of Java which has a non-nullable default value.

Syntax and declaration

Thus an Int value can be declared by 3 ways as mentioned below.

1. Mentioning type explicitly

val variable_name : Int = value

for example,

val number : Int = 100

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 : Int
variable_name = value

for example

//Declaring and Initializing separately
var number:Int
number = 100

Int Datatype Example Program in Kotlin

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

fun main(args: Array < String > ) {
    //Int type is inferred
    val num1 = 100 
    
    //Declaring an Int value immediately
    val num2: Int = 2147483647 
    
    //Print num1 and num2 values
    println("num1 Value : $num1")
    println("num2 Value : $num2")
}

Sample Output

num1 Value : 100
num2 Value : 2147483647

Type conversion syntax and declaration

//String to Int Conversion 
val variable_name = "string".toInt()

//Float and Double to Int Conversion 
val variable_name = float_variable.toInt()

Int type Conversion Example Program in Kotlin

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

fun main(args: Array < String > ) {
    //Conversion from String and Int type is inferred
    val num1 = "500".toInt() 
    
    //Conversion from String and Declaring an Int value immediately
    val num2: Int = "100".toInt() 
    
    val num3: Float = 1000.1000f
    //Conversion from Float
    val num4: Int = num3.toInt()
    
    val num5: Double = 2000.1000
    //Conversion from Double
    val num6: Int = num5.toInt()
    
    //Print values after conversion
    println("String to Int : num1 Value : $num1")
    println("String to Int : num2 Value : $num2")
    println("Float Value : num3 Value : $num3")
    println("Float to Int : num4 Value : $num4")
    println("Double Value : num5 Value : $num5")
    println("Double to Int : num6 Value : $num6")
}

Sample Output

String to Int : num1 Value : 500
String to Int : num2 Value : 100
Float Value : num3 Value : 1000.1
Float to Int : num4 Value : 1000
Double Value : num5 Value : 2000.1
Double to Int : num6 Value : 2000

How It Works

This Kotlin program demonstrates Int 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.