Read Data Input using Scanner in Kotlin

Definition

• Kotlin uses java.util.Scanner class to scan user inputs.
• To read a string, nextLine() method is used.
• Similarly, it has methods like nextInt(), nextLong() methods to get inputs of corresponding types.

Scanner Methods

Scanner scanner_variable = Scanner(System.`in`)

//Reading Int input
scanner_variable.nextInt()
//Reading Float Input
scanner_variable.nextFloat()
//Reading Double Input
scanner_variable.nextDouble()
//Reading Boolean Input
scanner_variable.nextBoolean()
//Reading Short Input
scanner_variable.nextShort()
//Reading Long Input
scanner_variable.nextLong()
//Reading String Input
scanner_variable.nextLine()

Syntax

Scanner scanner_variable = Scanner(System.`in`)
var variable_name = scanner_variable.nextLine()

For example,
var str = scanner.nextLine()

Read Data Input using Scanner Example Program in Kotlin

// Read Data Input in Kotlin example program
// Data Input Kotlin Programs, Basic Kotlin Programs

import java.util.Scanner

fun main(args: Array<String>) {

    val scanner  = Scanner(System.`in`)
    val num1 = scanner.nextInt()
    println("The input one is : $num1")
    val num2 = scanner.nextInt()
    println("The input two is : $num2")

    val sum = num1+num2

    println("The sum of the two inputs is : $sum")
}

Sample Output

Enter the inputs for addition
10
The input one is : 10
100
The input two is : 100
The sum of the two inputs is : 110

How It Works

Here is a step-by-step walkthrough of how the Kotlin program for Read Data Input using Scanner in Kotlin runs, line by line:

1. fun main(args: Array<String>) { — defines a function used by the program.
2. val scanner = Scanner(System.in) — reads a value entered by the user.
3. val num1 = scanner.nextInt() — reads a value entered by the user.
4. println("The input one is : $num1") — writes a line of output shown in the sample output.
5. val num2 = scanner.nextInt() — reads a value entered by the user.
6. println("The input two is : $num2") — writes a line of output shown in the sample output.
7. val sum = num1+num2 — declares or assigns a value the program uses.
8. println("The sum of the two inputs is : $sum") — writes a line of output shown in the sample output.

After running it, compare your console output with the Sample Output above. Try changing the values and re-running the program to see how the result changes — experimenting is the fastest way to understand the logic.