Difference between next() and nextline() in Java

One of the simplest methods for receiving input of the basic data types, also including int, double, and strings, in Java, is to use the Scanner class, which is part of the java.util.package. Time is a limited resource in competitive programming, thus employing the Scanner class is not the most effective solution in these circumstances.

Let's examine each approach separately using the following example:

next() Method

Input from the user is obtained using the next() function of the Scanner class. A Scanner class instance must be created before the next() method of both the Scanner class can be used. The next() method doesn't let the user's input through until it sees a white space (" "). The Scanner's subsequent entire token is returned as a result.

To comprehend how the next() technique utilizes user input, let's look at an example.

NextExpl.java

// importing the required classes and packages   
import java.util.Scanner;   
// creating the class NextExpl to understand nextLine() method of the Scanner class   
public class NextExpl {   
    // Driver code   
    public static void main(String args[]) {   
        String input;   
        // create an object for the Scanner class   
        Scanner s = new Scanner(System.in);   
        System.out.println(" Enter any string of your choice : ");   
        // taking the input from the user and storing it in the input  
        input = s.next();   
        System.out.println(" User input string : \n"+input);   
        // closing the Scanner class object   
        s.close();   
    }   
}

Output:

nextLine() Method

Input from the user is also taken using the nextLine() function of the Scanner class. Additionally, we must make an instance of both the Scanner class before we can utilize the nextLine() method. The nextLine() method has the ability to read input all the way across a line. When the user pushes the enter button or line change, it so halts reading the user's input.

Let's look at an illustration to understand better how well the nextLine() method works to capture user input.

// NextLineExpl.java

// importing the required classes and packages   
import java.util.Scanner;   
// creating the class NextLineExpl to understand nextLine() method of the Scanner class   
public class NextLineExpl {   
    // Driver code   
    public static void main(String args[]) {   
        String input;   
        // create an object for the Scanner class   
        Scanner s = new Scanner(System.in);   
        System.out.println(" Enter any string of your choice : ");   
        // taking the input from the user and storing it in the input  
        input = s.nextLine();   
          
        System.out.println(" User input string : \n"+input);   
        // closing the Scanner class object   
        s.close();   
    }   
}

Output:

Difference between the next() and the nextLine()

The following table compares the next() and nextLine() functions. It describes the differences between them:

S.no	next()	nextLine()
1	Up until the space character, it reads the input.	Up to the line change, it reads input.
2	It cannot read words with spaces between them.	This technique can be used to read words with spaces in them.
3	When it encounters a blank space, it stops reading its input.	When it encounters the character "n" or is pressed, it stops reading the input.
4	The technique moves the pointer to the same line after reading the input.	The procedure moves the pointer to the following line after reading the input.
5	The next() method's escape sequence is space.	The nextLine() method's escape sequence is "n."
6	Syntax: Scanner s = new Scanner(System.in); s.next();	Syntax: Scanner s = new Scanner(System.in); s.nextLine();