Read Number from Standard Input in Kotlin

In this article, we will understand how to read a number from standard input in Kotlin. The ?nextInt' method is used to read the number.

Below is a demonstration of the same

Suppose our input is

45

The desired output would be

The input value is 45

Algorithm

• Step 1 ? Start

• Step 2 ? Declare an integer: value

• Step 3 ? Define the integer

• Step 4 ? Read the values

• Step 5 ? Display the value

• Step 6 ? Stop

Example 1

In this example, we will read the number from the standard input using the Scanner(). First, we imported the java.util.Scanner to use the Scanner() for input ?

import java.util.Scanner

Then, a scanner object is created in the main() function ?

val input_scanner = Scanner(System.`in`)

The user enters the input using the System.`in`. After that, the nextLine() method reads the string value from the user ?

var input_string:String = input_scanner.nextLine()

Let us now see the complete example ?

import java.util.Scanner

fun main(args: Array<String>) {
   System.out.println("The required packages have been imported
");
   val input_scanner = Scanner(System.`in`)
   print("Enter an integer: ")

   var input_integer:Int = input_scanner.nextInt()
   println("The value is: $input_integer")
}

Output

The required packages have been imported
Enter an integer:45
The value is:5

Example 2

Here, we will create a custom function to read the number from the standard input using the Scanner ?

import java.util.Scanner

fun scan_value(){
   val input_scanner = Scanner(System.`in`)
   print("Enter an integer: ")
   var input_integer:Int = input_scanner.nextInt()
   println("The value is: $input_integer")
}

fun main(args: Array<String>) {
   System.out.println("The required packages have been imported
");
   scan_value()
}

Output

The required packages have been imported

Enter an integer:45
The value is: 45