Java Java lang.Long.highestOneBit()用法及代码示例

java.lang.Long.highestOneBit()是Java中的内置方法，该方法首先将数字转换为Binary，然后从左侧开始寻找第一个置位的位，然后重置其余位，然后返回值。用简单的语言，如果一个数字的二进制表达式包含一个设置位的最小值，则它返回2 ^(从right-1开始的最后一个设置位的位置)。如果二进制表达式不包含任何设置位，则返回0。

用法:

public static long highestOneBit(long num)
Parameters:
num - the number passed 
Returns:
long value by only considering highest 1 bit in the argument.

例子：

Input:9 
Output:8
Explanation:Binary Representation = 1001
It considers highest bit(at 4th from right) and now
reset rest of the bits i.e. 1000
so result = 1000 i.e. 8 or in simple terms, the last set 
bit position from right is at position 4, hence 2^3=8

Input:45
Output:32

以下示例程序旨在说明java.lang.Long.highestOneBit()函数：

程序1:

// Java program that demonstrates the use of 
// Long.highestOneBit() function 
  
// include lang package 
import java.lang.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        long l = 9; 
  
        // returns a long value with at most a 
        // single one-bit, in the position 
        // of the highest-order ("rightmost") 
        // one-bit in the specified long value. 
        System.out.println("highest one bit = " + Long.highestOneBit(l)); 
  
        l = 45; 
        System.out.println("highest one bit = " + Long.highestOneBit(l)); 
    } 
}

输出：

highest one bit = 8
highest one bit = 32

注意：负数的最高位在每种情况下都将始终相同，因此，不管数字是多少，每个负数的输出都将相同。

程序2:下面的程序演示了传递负数时函数的使用。

// java program that demonstrates the use of 
// Long.highestOneBit() function 
// negative number 
  
// include lang package 
import java.lang.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        long l = -15; 
  
        // prints the binary of a negative expression 
        System.out.println("Binary = " + Long.toBinaryString(l)); 
  
        // returns a long value with at 
        // most a single one-bit, in the position 
        // of the highest-order ("rightmost") 
        // one-bit in the specified int value. 
        System.out.println("Highest one bit = " + Long.highestOneBit(l)); 
    } 
}

输出：

Binary = 1111111111111111111111111111111111111111111111111111111111110001
Highest one bit = -9223372036854775808

当将十进制字符串值作为参数传递时，它将返回错误消息。
程序3:在参数中传递十进制值时。

// java program that demonstrates the 
// Long.highestOneBit() function 
// decimal value in argument 
  
// include lang package 
import java.lang.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        System.out.println("highest one bit = " + Long.highestOneBit(12.34)); 
    } 
}

输出：

prog.java:13:error:incompatible types:possible lossy conversion from double to long
        System.out.println("highest one bit = " + Long.highestOneBit(12.34));

程序3:在参数中传递字符串值时。

// java program that demonstrates the 
// Long.highestOneBit() function 
// string value in argument 
  
// include lang package 
import java.lang.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        System.out.println("highest one bit = " + Long.highestOneBit("12")); 
    } 
}

输出：

prog.java:13:error:incompatible types:String cannot be converted to long
        System.out.println("highest one bit = " + Long.highestOneBit("12"));

相关用法

注：本文由纯净天空筛选整理自gopaldave大神的英文原创作品 Java lang.Long.highestOneBit() method in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。