Java Java () 方法与示例

Java.lang.Long.highestOneBit()是Java中的一个内置方法，它首先将数字转换为二进制，然后从左边开始查找第一个设置位，然后重置其余位，然后返回值。用简单的语言来说，如果一个数字的二进制表达式至少包含一个设置位，它返回 2^（从右 1 开始的最后一个设置位位置）。如果二进制表达式不包含任何设置位，则返回 0。

句法：

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

下面的程序说明了Java.lang.Long.highestOneBit()函数：

方案一：

// 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，因此无论数字如何，每个负数的输出都是相同的。

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

当十进制字符串值作为参数传递时，它会返回错误消息。
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"));