Taking Java Input: Using different types of next() methods according to Data Types

To take inputs in Java, we use next() method. But next() only takes String input until a space occurs. So in this blog we will learn the in details about inputs in Java.

First of all we need to import Java's util package to use the Scanner class that have next() method in it. To do that we need to write below code:

import java.util.*;    // importing all classes and interfaces from util package

Otherwise, we can only import Scanner class too:

import java.util.Scanner    // importing only Scanner Class

The next() method is a part of the java.util.Scanner class in Java. This method finds and returns the next complete token from the scanner which is in use. A token is recognized as a complete entity in string form, such as a word.

Using Scanner class we will then create a object of any name. Lets take sc as the object name →

Scanner sc = new Scanner(System.in);

Now object sc will finally let us use the next() method to catch inputs from uses written in Terminal. Before we do that, we also need to store the input some where to work later. As next() only takes String values, we will store it in a String variable (lets name that variable str) →

String str= sc.next();

Full Code & Syntax

The syntax of the next() method is:

import java.util.Scanner;

public class MyClass {
    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a Input: ");
        String str= sc.next();
        System.out.println("User's Input: " + str);
    }
}

Here is output →

Functionality

When you call the next() method, it scans the input for the next token, skipping over any delimiters (which are whitespace by default). Once it finds a token, it returns that token. If no more tokens are available, it throws a NoSuchElementException.

In this code, the next() method waits for the user to input a string and then assigns that string to the str variable.

Different Data Types & next() methods

While the next() method is useful, it’s important to note that it only returns the next token. If the user inputs multiple words, next() will only return the first word. To get a full line of input, you should use the nextLine() method instead. Look The Example Below →

Look it only taking the first word from given String input

As a solution Java has different methods for taking different Data Types →

1. nextInt(): This method reads an int value from the user.

Scanner input = new Scanner(System.in);
System.out.println("Enter an integer: ");
int data = input.nextInt();
System.out.println("Using nextInt(): " + data);

2. nextDouble(): This method reads a double value from the user.

Scanner input = new Scanner(System.in);
System.out.print("Enter Double value: ");
double value = input.nextDouble();
System.out.println("Using nextDouble(): " + value);

3. nextLine(): This method reads a line of text from the user.

Scanner input = new Scanner(System.in);
System.out.print("Enter your name: ");
String name = input.nextLine();
System.out.println("My name is " + name);

4. next(): This method reads a word from the user.

5. nextFloat(): This method reads a float value from the user.

6. nextBoolean(): This method reads a boolean value from the user.

7. nextByte(): This method reads a byte value from the user.

8. nextShort(): This method reads a short value from the user.

9. nextLong(): This method reads a long value from the user.

These all available methods from Scanner class are used to capture different data types as mentioned above.

Conclusion

The next() method other similar methods in Java’s Scanner class are ways for parsing input as we need in different use cases. Whether you’re reading user input or parsing a file, understanding how to use next() will be beneficial.