Java中的 Scanner useRadix() 方法和示例

Java.util.Scanner类的useRadix(radix)方法将此扫描仪的默认基数设置为指定的基数。扫描仪的基数会影响其默认数字匹配正则表达式的元素。

句法：

public Scanner useRadix(int radix)

参数：该函数接受一个强制参数radix ，它指定扫描数字时使用的基数。

返回值：该函数返回此扫描仪对象。

例外：如果基数小于字符.MIN_RADIX或大于字符.MAX_RADIX ，则抛出IllegalArgumentException 。

下面的程序说明了上述函数：

方案一：

// 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);
        }
    }
}

输出：

String:
Geeksforgeeks has Scanner Class Methods

Old Radix: 10

New Radix: 12

程序 2：异常演示

// 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);
        }
    }
}

输出：

String:
Geeksforgeeks has Scanner Class Methods

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

参考： https: Java/util/Scanner.html#useRadix(int)