在给定位置修改一个位-yiteyi-C++库

给定一个数字 N ，一个职位 P 和一个二进制值 B ，我们需要将n中位置p处的位更改为值b。

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例如：

Input : n = 7, p = 2, b = 0Output : 37 is 00000111 after clearing bit at 2rd position, it becomes 0000011.Input : n = 7, p = 3, b = 1Output : 157 is 00000111 after setting bit at 3rd position it becomes 00001111.

推荐：请尝试你的方法 {IDE} 首先，在进入解决方案之前。

We first create a mask that has set bit only at given position using bit wise shift.      mask = 1 << positionThen to change value of bit to b, we firstmake it 0 using below operation      value & ~maskAfter changing it 0, we change it to b bydoing or of above expression with following(b << p) & mask, i.e., we return      ((n & ~mask) | (b << p))

以下是上述步骤的实施情况：

C++

                         // CPP program to modify a bit at position                       
                         // p in n to b.                       
                         #include <bits/stdc++.h>                       
                         using                                     namespace                                     std;                       
           
                         // Returns modified n.                       
                         int                                     modifyBit(                                     int                                     n,                                     int                                     p,                                     int                                     b)                       
                         {                       
                                                 int                                     mask = 1 << p;                       
                                                 return                                     ((n & ~mask) | (b << p));                       
                         }                       
           
                         // Driver code                       
                         int                                     main()                       
                         {                       
                                                 cout << modifyBit(6, 2, 0) << endl;                       
                                                 cout << modifyBit(6, 5, 1) << endl;                       
                                                 return                                     0;                       
                         }                       

JAVA

                         // Java program to modify a bit                       
                         // at position p in n to b.                       
                         import                                     java.io.*;                       
           
                         class                                     GFG                       
                         {                       
                                   
                         // Returns modified n.                       
                         public                                     static                                     int                                     modifyBit(                                     int                                     n,                       
                                                 int                                     p,                       
                                                 int                                     b)                       
                         {                       
                                                 int                                     mask =                                     1                                     << p;                       
                                                 return                                     (n & ~mask) |                       
                                                 ((b << p) & mask);                       
                         }                       
                                                 // Driver Code                       
                                                 public                                     static                                     void                                     main (String[] args)                       
                                                 {                       
                                                 System.out.println(modifyBit(                                     6                                     ,                                     2                                     ,                                     0                                     ));                       
                                                 System.out.println (modifyBit(                                     6                                     ,                                     5                                     ,                                     1                                     ));                       
                                                 }                       
                         }                       
           
                         // This code is contributed by m_kit                       

Python3

                         # Python3 program to modify a bit at position                       
                         # p in n to b.                       
           
                         # Returns modified n.                       
                         def                                     modifyBit( n,  p,  b):                       
                                                 mask                                     =                                     1                                     << p                       
                                                 return                                     (n & ~mask) | ((b << p) & mask)                       
                                   
                         # Driver code                       
                         def                                     main():                       
                                                 print                                     (modifyBit(                                     6                                     ,                                     2                                     ,                                     0                                     ))                       
                                                 print                                     (modifyBit(                                     6                                     ,                                     5                                     ,                                     1                                     ))                       
                                   
                         if                                     __name__                                     =                                     =                                     '__main__'                                     :                       
                                                 main()                       
                         # This code is contributed by PrinciRaj1992                       

C#

                         // C# program to modify a bit                       
                         // at position p in n to b.                       
                         using                                     System;                       
           
                         class                                     GFG                       
                         {                       
                         // Returns modified n.                       
                         public                                     static                                     int                                     modifyBit(                                     int                                     n,                       
                                                 int                                     p,                       
                                                 int                                     b)                       
                         {                       
                                                 int                                     mask = 1 << p;                       
                                                 return                                     (n & ~mask) |                       
                                                 ((b << p) & mask);                       
                         }                       
           
                                                 // Driver Code                       
                                                 static                                     public                                     void                                     Main ()                       
                                                 {                       
                                   
                                                 Console.WriteLine(modifyBit(6, 2, 0));                       
                                                 Console.WriteLine(modifyBit(6, 5, 1));                       
                                                 }                       
                         }                       
           
                         // This code is contributed by ajit                       

PHP

                         <?php                       
                         // PHP program to modify a bit                       
                         // at position p in n to b.                       
           
                         // Returns modified n.                       
                         function                                     modifyBit(                                     $n                                     ,                                     $p                                     ,                                     $b                                     )                       
                         {                       
                                                 $mask                                     = 1 <<                                     $p                                     ;                       
                                                 return                                     (                                     $n                                     & ~                                     $mask                                     ) |                       
                                                 ((                                     $b                                     <<                                     $p                                     ) &                                     $mask                                     );                       
                         }                       
           
                                                 // Driver code                       
                                                 echo                                     modifyBit(6, 2, 0),                                     ""                                     ;                       
                                                 echo                                     modifyBit(6, 5, 1) ,                                     ""                                     ;                       
                                   
                         // This code is contributed by ajit                       
                         ?>                       

Javascript

                         <script>                       
           
                         // Javascript program to modify a bit                       
                         // at position p in n to b.                       
           
                         // Returns modified n.                       
                         function                                     modifyBit(n, p, b)                       
                         {                       
                                                 let mask = 1 << p;                       
                                                 return                                     (n & ~mask) |                       
                                                 ((b << p) & mask);                       
                         }                       
           
                         // Driver code                       
                         document.write(modifyBit(6, 2, 0) +                                     "<br/>"                                     );                       
                         document.write(modifyBit(6, 5, 1));                       
           
                         // This code is contributed by susmitakundugoaldanga                       
           
                         </script>                       

输出：

 2 38

时间复杂性： O（1）

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