BigInteger类testBit()方法 (BigInteger Class testBit() method)

• testBit() method is available in java.math package.

  testBit()方法在java.math包中可用。

• testBit() method is used to check whether the testing bit indexed at the given position is set or not in this BigInteger.

  testBit()方法用于检查在此BigInteger中是否设置了在给定位置索引的测试位。

• testBit() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.

  testBit()方法是一个非静态方法，只能通过类对象访问，如果尝试使用类名称访问该方法，则会收到错误消息。

• testBit() method may throw an exception at the time of testing set bit.

  在测试设置位时， testBit()方法可能会引发异常。

  ArithmeticException: This exception may throw when the given parameter holds value less than 0.

  ArithmeticException ：当给定参数的值小于0时，可能引发此异常。

Syntax:

句法：

public boolean testBit(int pos);

Parameter(s):

参数：

• int pos – represents the position of bit to be tested.

  int pos –表示要测试的位的位置。

Return value:

返回值：

The return type of this method is BigInteger, it returns true when the tested bit is set at the given position otherwise it returns false.

此方法的返回类型为BigInteger ，当将测试位设置在给定位置时返回true，否则返回false。

Example:

例：

// Java program to demonstrate the example // of boolean testBit(int pos) method of BigIntegerimport java.math.*;public class TestBitOfBI {
       public static void main(String args[]) {
           // Initialize a variable str        String str = "10";        // Initialize a BigInteger object         BigInteger b_int = new BigInteger(str);        // Display b_int        System.out.println("b_int: " + b_int);        // Display Binary representation of  str         System.out.println("Binary Representation of 10: 1010 ");        System.out.println();        // checks whether the bit is set "1" at the        // given indices in this BigInteger or not and        // binary value of 10 is 1010 so it returns         // false because the bit is not set at the given        // indices 0        boolean status = b_int.testBit(0);        System.out.println("b_int.testBit(0): " + status);        // checks whether the bit is set "1" at the        // given indices in this BigInteger or not and        // binary value of 10 is 1010 so it returns         // true because the bit is set at the given        // indices 1        status = b_int.testBit(1);        System.out.println("b_int.testBit(1): " + status);    }}

Output

输出量

b_int: 10Binary Representation of 10: 1010 b_int.testBit(0): falseb_int.testBit(1): true

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