Java Scanner nextLong() Method

The nextLong() is a Java Scanner class method which is used to scan the next token of the input as a long. There is two different types of Java nextLong() method which can be differentiated depending on its parameter. These are:

Java Scanner nextLong() Method
Java Scanner nextLong(int radix) Method

nextLong() Method

This is a Java Scanner class method which is used to scan the next token of the input as a long in the default radix.

nextLong(int radix) Method

This is an inbuilt method of Java Scanner class which is used to scan the next token of the input as a long in the specified radix.

Syntax

Following is the declaration of nextLong() method:

public long nextLong()
public long nextLong(int radix)

Parameter

DataType	Parameter	Description	Required/Optional
int	radix	It is used to interpret the token as a int value.	Required

Returns

The nextLong() method returns the long value scanned from the input.

Exceptions

IllegalStateException- This method throws exception if the innvocation is done after the scanner has been closed.

IllegalArgumentException- It throws this exception if the specified radix is out of range.

InputMismatchException- It throws this exception if the next token does not match the Integer regular expression, or is out of range.

Compatibility Version

Java 1.5 and above

Example 1

import java.util.*;
public class ScannerNextLongExample1 {  
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		System.out.print("Enter the Number you want: ");
	      long num = input.nextLong();
	      System.out.println("Output value: "+(num * (num + 2)) / 2);
	      input.close();
	      }
}

Output:

Enter the Number you want: 880
Output value: 388080

Example 2

import java.util.*;
public class ScannerNextLongExample2 {  
	public static void main(String[] args) {
	     @SuppressWarnings("resource")
	     Scanner in = new Scanner(System.in);
           long a, b, x, y;
           System.out.print("Enter Value of a: ");
           a = in.nextLong();       
           System.out.print("Enter Value of x: ");
           x = in.nextLong();
           System.out.print("Enter Value of b: ");
           b = in.nextLong();
           System.out.print("Enter Value of y: ");
           y = in.nextLong();       
           if (a >= b) {
               System.out.println("Output: "+a);
               return;
           }
           while (a <= b) {
               if (a + x >= b) {
                   System.out.println("Output: "+b);
                   return;
               }
               a += x;
               b -= y;
           }
           System.out.println("Output: "+a);
           in.close();
	     }
}

Output:

Enter Value of a: 12345
Enter Value of x: 123456
Enter Value of b: 1234567
Enter Value of y: 1234
Output: 1223461

Example 3

import java.util.*;
public class ScannerNextLongExample3 {  
	public static void main(String[] args) {
		 String str = "JavaTpoint.com 13 + 13 = 26.0 true ";
	      Long l = 123456789098765432L;
	      str = str + l;
	      Scanner scanner = new Scanner(str);
	      while (scanner.hasNext()) {
	         System.out.println("Not Found: " + scanner.next());
	         if (scanner.hasNextLong()) {
	            System.out.println("Found: " + scanner.nextLong());
	         }
	      }
	      scanner.close();
	}
}

Output:

Not Found: JavaTpoint.com
Found: 13
Not Found: +
Found: 13
Not Found: =
Not Found: 26.0
Not Found: true
Found: 123456789098765432

Example 4

import java.util.*;
public class ScannerNextLongExample4 {  
	public static void main(String[] args) {
		//Initialize the scanner
		Scanner scan = new Scanner("5555 B35 -2555 -755 51D");
		while(scan.hasNext()){
			//Printing int tokens of base 16
			System.out.println(scan.nextLong(16));
		}
		scan.close();
	}
}

Output:

Example 5

import java.util.*;
public class ScannerNextLongExample5 {  
	public static void main(String[] args) {	
	    String str = " 11 Java 11 + 11 = 22.0 true 5550000000000000000000L";
	    Scanner scanner = new Scanner(str);
	    while (scanner.hasNext()) {
	       System.out.println("Not Found :" + scanner.next());
	       if (scanner.hasNextLong()) {
	          System.out.println("Found :" + scanner.nextLong(2050));
	       }
	    }
	    scanner.close();
	}
}

Output:

Not Found :11
Not Found :Java
Exception in thread "main" java.lang.IllegalArgumentException: radix:2050
	at java.base/java.util.Scanner.setRadix(Scanner.java:1368)
	at java.base/java.util.Scanner.nextLong(Scanner.java:2370)
	at myPackage.ScannerNextLongExample5.main(ScannerNextLongExample5.java:11)

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