切换最后m位

给定一个非负数n 。问题是要切换n的二进制表示形式中的最后m位。切换操作将位0翻转为1 ，将位1翻转为0 。

约束： 1 <= m <= n。

例子：

Input : n = 21, m = 2
Output : 22
(21)10 = (10101)2
(22)10 = (10110)2
The last two bits in the binary
representation of 21 are toggled.

Input : n = 107, m = 4
Output : 100

方法：以下是步骤：

1. 计算num =(1 << m)–1。这将生成具有m个位数的数字num ，并且将全部设置。
2. 现在，执行n = n ^ num 。这将切换n中的最后m位。

C++

// C++ implementation to
// toggle the last m bits
#include 
using namespace std;
  
// function to toggle
// the last m bits
unsigned int toggleLastMBits
         (unsigned int n, unsigned int m)
{
      
    // calculating a number 
    // 'num' having 'm' bits
    // and all are set. 
    unsigned int num = (1 << m) - 1;
  
    // toggle the last m bits
    // and return the number
    return (n ^ num);
}
  
// Driver code
int main()
{
    unsigned int n = 107;
    unsigned int m = 4;
    cout << toggleLastMBits(n, m);
    return 0;
}

Java

// Java implementation to
// toggle the last m bits
import java.util.*;
import java.lang.*;
  
public class GfG{
      
    // function to toggle
    // the last m bits
    public static int toggleLastMBits
                      (int n, int m)
    {
          
        // calculating a number 
        // 'num' having 'm' bits
        // and all are set
        int num = (1 << m) - 1;
   
        // toggle the last m bits
        // and return the number
        return (n ^ num);
    }
      
    // Driver function
    public static void main(String argc[]){
        int n = 107;
        int m = 4;
        n =  toggleLastMBits(n, m);
        System.out.println(n);
                
    }
}
  
// This code is contributed by Sagar Shukla.

Python3

# Python implementation to
# toggle the last m bits
  
# function to toggle
# the last m bits
def toggleLastMBits(n,m):
  
    # calculating a number 
    # 'num' having 'm' bits
    # and all are set. 
    num = (1 << m) - 1
   
    # toggle the last m bits
    # and return the number
    return (n ^ num)
  
# Driver code
  
n = 107
m = 4
print(toggleLastMBits(n, m))
  
# This code is contributed
# by Anant Agarwal.

C#

// C# implementation to
// toggle the last m bits
using System;
  
namespace Toggle
{
    public class GFG
    {     
                  
    // Function to toggle the last m bits
    public static int toggleLastMBits(int n, int m)
    {
          
        // Calculating a number 'num' having
        // 'm' bits and all are set
        int num = (1 << m) - 1;
  
        // Toggle the last m bits
        // and return the number
        return (n ^ num);
    }
      
    // Driver Code
    public static void Main() {
          
        int n = 107, m = 4;
        n = toggleLastMBits(n, m);
        Console.Write(n);
                  
    }
    }
}
  
// This code is contributed by Sam007.

输出：

100