Java中的整数reverse()方法

Java.lang.Integer.reverse() 是Java中的一个内置方法，用于返回指定int 值的二进制补码二进制表示中位的倒序。

句法：

public static int reverse(int a)

参数：参数a是一个整数值，其位将被反转。

返回值：该方法返回将指定int值中位的顺序颠倒得到的值。

例子：

Input: 86
Output: 1778384896
Explanation:
Consider an integer a = 86
Binary Representation = 1010110
The number of one bit = 4 
After reversing it is = 1778384896

Input: 168
Output: 352321536

下面的程序说明了Java.lang.Integer.reverse() 方法：
程序 1：对于正数。

// Java program to illustrate the
// Java.lang.Integer.reverse() method
import java.lang.*;
  
public class geeks {
  
    public static void main(String[] args)
    {
  
        int a = 168;
        System.out.println("Number = " + a);
  
        // It returns the value obtained by reversing order of the bits
        System.out.println("By reversing we get = " + Integer.reverse(a));
    }
}

输出：

Number = 168
By reversing we get = 352321536

程序 2：对于负数。

// Java program to illustrate the
// Java.lang.Integer.reverse() method
import java.lang.*;
  
public class geeks {
  
    public static void main(String[] args)
    {
  
        int a = -72;
        System.out.println("Number = " + a);
  
        // It returns the value obtained by reversing order of the bits
        System.out.println("By reversing we get = " + Integer.reverse(a));
    }
}

输出：

Number = -72
By reversing we get = 503316479

程序 3：对于十进制值和字符串。
注意：当十进制值或字符串作为参数传递时，它会引发错误消息。

// Java program to illustrate the
// Java.lang.Integer.reverse() method
import java.lang.*;
  
public class geeks {
  
    public static void main(String[] args)
    {
  
        int a = 37.9;
        System.out.println("Number = " + a);
  
        // It returns the value obtained by reversing order of the bits in
        // the specified int value
        System.out.println("By reversing we get = " + Integer.reverse(a));
        a = "21";
        System.out.println("Number = " + a);
  
        // It returns the value obtained by reversing order of the bits in
        // the specified int value
        System.out.println("By reversing we get = " + Integer.reverse(a));
    }
}

输出：

prog.java:9: error: incompatible types: possible lossy conversion from double to int
    int a = 37.9;
            ^
prog.java:17: error: incompatible types: String cannot be converted to int
     a = "21";
         ^
2 errors