Kotlin Output

Definition of Kotlin Output

Kotlin output refers to displaying information or results from a Kotlin program to the console or other output devices. It lets developers provide feedback or present data in a readable format. There are various ways to perform output operations in Kotlin, with println() and print() being commonly used methods.

• println() adds a new line at the end of the output.
• print() does not add a new line.

Both functions internally call System.out object's println() and print() methods from the Java standard library.

Standard Output in Kotlin

Standard output in Kotlin is the default way of displaying information to the console. It is crucial for communicating with users and providing relevant information during program execution. The println function is typically used, and it adds a new line after printing, ensuring each output appears on a new line. Effective use of standard output enhances the user experience and allows for clear program interaction.

System.out.println() Method

The System.out.println() method is often used in Java programs to print output to the console. To use this method, type System.out.println() followed by parentheses containing the text or value you want to display.

For example:

System.out.println("Hello")


Differences between print() and println()

• print(): Prints the output without moving the cursor to a new line.
• println(): Prints the output and moves the cursor to the beginning of the next line.

The println() method automatically appends a newline character, so you don't need to include \n manually.

Println Data Output

In Kotlin, the println function is used to print output and move the cursor to the next line. It's simple to use: just type println() followed by the content you want to display in parentheses. This content can be strings, variables, or expressions.

Example:

println("Welcome!")
println(2 * 5)

The output will be on separate lines due to the behavior of println().

Print Function

The print function in Kotlin displays output without adding a newline character. It is similar to println but keeps the cursor on the same line.

For example:

print("Hello, ")
print("World!")

Output: Hello, World!

The print function is useful when you want multiple outputs on the same line or need control over formatting.

Input from User in Kotlin

Taking input from the user is essential for interactive programs. In Kotlin, user input can be gathered in several ways, such as through command line input, files, or even graphical interfaces. Some commonly used techniques include standard input/output streams, using the Scanner class, and validating input for errors.

Scanner Class

The Scanner class in Kotlin is a versatile tool for reading input from the console or other sources. To use it, add the following import at the top of your program:

import java.util.Scanner


Create an instance of the class:

val scanner = Scanner(System.in)


This allows you to read from the console. The Scanner class has methods like:

• nextInt() - Reads an integer.
• nextDouble() - Reads a double.
• nextLine() - Reads a line of text.
• next() - Reads a single word or token.

Always handle exceptions like NoSuchElementException for hasNext and next, and InputMismatchException for nextInt and nextDouble.

User Input Operations

Kotlin provides several methods for user input operations. The most common one is readLine(), which reads a line as a string:

val userInput = readLine()


For boolean input:

val userBool = scanner.nextBoolean()


Kotlin also provides methods like nextFloat(), nextLong(), and nextDouble() for reading different data types using the Scanner class.

To use these methods:

import java.util.Scanner
val scanner = Scanner(System.in)

This allows for various user input operations that enable program interaction and data collection.