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Java Scanner nextLong() Method with Example

Scanner Class nextLong() method: Here, we are going to learn about the nextLong() method of Scanner Class with its syntax and example.
Submitted by Preeti Jain, on March 24, 2020

Scanner Class nextLong() method

Syntax:

    public long nextLong();
    public long nextLong(int rad);

• nextLong() method is available in java.util package.
• nextLong() method is used to read the next token of the input as a long value at the implicit radix of this Scanner.
• nextLong(int rad) method is used to read the next token of the input as a long value at the explicit or given radix(rad) of this Scanner.
• These methods may throw an exception at the time of representing an input as a long value.
  • InputMismatchException: This exception may throw when the next token of the input mismatch.
  • NoSuchElementException: This exception may throw when no such element exists.
  • IllegalStateException: This exception may throw when this Scanner is not opened.
• These are non-static methods and it is accessible with the class object only and if we try to access these methods with the class name then we will get an error.

Parameter(s):

• In the first case, nextLong(),
  • It does not accept any parameter.
• In the second case, nextLong(int rad),
  • int rad – represents the radix used to manipulate the token as a long value.

Return value:

In both the cases, the return type of the method is long, it retrieves the long value read from the input.

Example 1:

// Java program to demonstrate the example 
// of nextLong() method of Scanner

import java.util.*;
import java.util.regex.*;

public class NextLong {
 public static void main(String[] args) {
  String str = "Java Programming! 3 * 8= 24 + b";
  long l = 101245l;

  // Instantiates Scanner
  Scanner sc = new Scanner(str);

  while (sc.hasNext()) {
   // By using nextLong() method isto
   // return the next token as a 
   // long at the implicit radix
   if (sc.hasNextLong()) {
    long next_l = sc.nextLong();
    System.out.println("sc.nextLong()): " + next_l);
   }
   System.out.println(sc.next());
  }

  // Scanner closed
  sc.close();
 }
}

Output

Java
Programming!
sc.nextLong()): 3
*
8=
sc.nextLong()): 24
+
b

Example 2:

import java.util.*;
import java.util.regex.*;

public class NextLong {
 public static void main(String[] args) {
  String str = "Java Programming! 3 * 8= 24 + b";
  long l = 101245l;

  // Instantiates Scanner
  Scanner sc = new Scanner(str);

  while (sc.hasNext()) {
   // By using nextLong(9) method isto
   // return the next token as a 
   // long at the explicit radix
   if (sc.hasNextLong()) {
    long next_l = sc.nextLong(9);
    System.out.println("sc.nextLong(9)): " + next_l);
   }
   System.out.println(sc.next());
  }

  // Scanner closed
  sc.close();
 }
}

Output

Java
Programming!
sc.nextLong(9)): 3
*
8=
sc.nextLong(9)): 22
+
b