Java User Input by (Scanner) class

What is Scanner Class in java computer program :

The `Scanner` class in Java, part of `java.util`, facilitates user input from keyboard, files, or strings. It offers methods to read various data types, supports delimiter customization, and resource management. It's crucial to handle exceptions and close the scanner to prevent resource leaks.

Here's a brief overview of how to use Scanner for user input:

1. Import the Scanner class: You need to import the Scanner class at the beginning of your Java program:

                        import java.util.Scanner;

        2. Create a Scanner object: Initialize a Scanner object to read input from the desired source. Typically, you'll use System.in for standard input (keyboard):

                        Scanner scanner = new Scanner(System.in);

        3. Read user input: Use various methods provided by the Scanner class to read input. For example, nextLine() reads a line of text, nextInt() reads an integer, nextDouble() reads a double, etc.

                       System.out.print("Enter your name: ");
                       String name = scanner.nextLine();

         4.Close the Scanner object: Once you're done reading input, it's good practice to close the Scanner object to release system resources:

                       scanner.close();

Example of  Java Code :

import java.util.Scanner;
class sndp
{
    
public static void main(String args[])
{
Scanner scanner = new Scanner(System.in);

System.out.println("Enter Your Name");

String name = scanner.nextLine();

System.out.println("Hello I am "+name);

scanner.close();
    
}
}
 

Here's a list of commonly used methods provided by the `Scanner` class for reading different types of input from the user:

1. nextLine(): Reads a line of text entered by the user, including whitespace characters, and returns it as a `String`.

2. nextInt(): Reads the next token entered by the user as an integer and returns it.

3. nextFloat(): Reads the next token entered by the user as a float and returns it.

4. nextDouble(): Reads the next token entered by the user as a double and returns it.

5. nextBoolean(): Reads the next token entered by the user as a boolean and returns it.

6. nextByte(): Reads the next token entered by the user as a byte and returns it.

7. nextShort(): Reads the next token entered by the user as a short and returns it.

8. nextLong(): Reads the next token entered by the user as a long and returns it.

9. hasNext(): Returns `true` if there is another token in the input, otherwise returns `false`.

10. hasNextLine(): Returns `true` if there is another line of input, otherwise returns `false`.

11. hasNextInt(): Returns `true` if the next token in the input can be interpreted as an integer, otherwise returns `false`.

12. hasNextFloat(): Returns `true` if the next token in the input can be interpreted as a float, otherwise returns `false`.

13. hasNextDouble(): Returns `true` if the next token in the input can be interpreted as a double, otherwise returns `false`.

14. hasNextBoolean(): Returns `true` if the next token in the input can be interpreted as a boolean, otherwise returns `false`.

15. hasNextByte(): Returns `true` if the next token in the input can be interpreted as a byte, otherwise returns `false`.

16. hasNextShort(): Returns `true` if the next token in the input can be interpreted as a short, otherwise returns `false`.

17. hasNextLong(): Returns `true` if the next token in the input can be interpreted as a long, otherwise returns `false`.

These methods provide flexibility for reading different types of input from the user in a Java program using the `Scanner` class.