Scanner useRadix() method in Java with Examples

The useRadix(radix) method of java.util.Scanner class sets this scanner’s default radix to the specified radix. A scanner’s radix affects elements of its default number matching regular expressions.

Syntax:

public Scanner useRadix(int radix)

Parameters: The function accepts a mandatory parameter radix which specifies the radix to use when scanning numbers.

Return Value: The function returns this scanner object.

Exceptions: If the radix is less than Character.MIN_RADIX or greater than Character.MAX_RADIX, then an IllegalArgumentException is thrown.

Below programs illustrate the above function:

Program 1:

// Java program to illustrate the
// useRadix() method of Scanner class in Java

import java.util.*;

public class GFG1 {
    public static void main(String[] argv)
        throws Exception
    {

        try {

            String s = "Geeksforgeeks has Scanner Class Methods";

            // create a new scanner
            // with the specified String Object
            Scanner scanner = new Scanner(s);

            // print the line of the scanner
            System.out.println("String:\n"
                               + scanner.nextLine());

            // display the Old radix
            System.out.println("\nOld Radix: "
                               + scanner.radix());

            // change the radix
            // of the scanner to 12
            scanner.useRadix(12);

            // display the new radix
            System.out.println("\nNew Radix: "
                               + scanner.radix());

            // close the scanner
            scanner.close();
        }

        catch (IllegalArgumentException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

Output:

String:
Geeksforgeeks has Scanner Class Methods

Old Radix: 10

New Radix: 12

Program 2: Exception demonstrated

// Java program to illustrate the
// useRadix() method of Scanner class in Java

import java.util.*;

public class GFG1 {
    public static void main(String[] argv)
        throws Exception
    {

        try {

            String s = "Geeksforgeeks has Scanner Class Methods";

            // create a new scanner
            // with the specified String Object
            Scanner scanner = new Scanner(s);

            // print the line of the scanner
            System.out.println("String:\n"
                               + scanner.nextLine());

            // display the Old radix
            System.out.println("\nOld Radix: "
                               + scanner.radix());

            // change the radix
            // of the scanner to 64
            scanner.useRadix(64);

            // display the new radix
            System.out.println("\nNew Radix: "
                               + scanner.radix());

            // close the scanner
            scanner.close();
        }

        catch (IllegalArgumentException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

Output:

String:
Geeksforgeeks has Scanner Class Methods

Old Radix: 10
Exception thrown : java.lang.IllegalArgumentException: radix:64

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html#useRadix(int)