Set all the bits in given range of a number

Given a non-negative number n and two values l and r. The problem is to set the bits in the range l to r in the binary representation of n, i.e, to unset bits from the rightmost lth bit to the rightmost r-th bit.
Constraint: 1 <= l <= r <= number of bits in the binary representation of n.

Examples :

Input : n = 17, l = 2, r = 3
Output : 23
(17)₁₀ = (10001)₂
(23)₁₀ = (10111)₂
The bits in the range 2 to 3 in the binary
representation of 17 are set.

Input : n = 50, l = 2, r = 5
Output : 62

Recommended: Please solve it on “PRACTICE” first, before moving on to the solution.

Approach: Following are the steps:

1. Find a number 'range' that has all set
   bits in given range. And all other bits
   of this number are 0.
     range = (((1 << (l - 1)) - 1) ^ 
              ((1 << (r)) - 1));

2. Now, perform "n = n | range". This will 
   set the bits in the range from l to r 
   in n.

C++

// C++ implementation to Set bits in 
// the given range 
#include <iostream> 
using namespace std; 
  
// function to toggle bits in the given range 
int setallbitgivenrange(int n, int l, int r) 
{ 
    // calculating a number 'range' having set 
    // bits in the range from l to r and all other 
    // bits as 0 (or unset). 
    int range = (((1 << (l - 1)) - 1) ^     
                ((1 << (r)) - 1)); 
  
    return (n | range); 
} 
  
// Driver code 
int main() 
{ 
    int n = 17, l = 2, r = 3; 
    cout << setallbitgivenrange(n, l, r); 
    return 0; 
} 

Java

// java implementation to Set bits in 
// the given range 
import java.util.*; 
  
class GFG 
{ 
      
    // function to toggle bits in the  
    // given range 
    static int setallbitgivenrange(int n, 
                             int l, int r) 
    { 
          
        // calculating a number 'range'  
        // having set bits in the range  
        // from l to r and all other 
        // bits as 0 (or unset). 
        int range = (((1 << (l - 1)) - 1) ^  
                    ((1 << (r)) - 1)); 
      
        return (n | range); 
    } 
      
    // Driver code 
    public static void main(String[] args) 
    { 
        int n = 17, l = 2, r = 3; 
          
        System.out.println(setallbitgivenrange( 
                                      n, l, r)); 
    } 
      
} 
  
// This code is contributed by Sam007. 

Python3

# Python3 implementation to Set  
# bits in the given range 
  
# Function to toggle bits 
# in the given range 
def setallbitgivenrange(n, l, r): 
  
    # calculating a number 'range' 
    # having set bits in the range 
    # from l to r and all other 
    # bits as 0 (or unset). 
    range = (((1 << (l - 1)) - 1) ^  
                ((1 << (r)) - 1)) 
  
    return (n | range) 
  
# Driver code 
n, l, r = 17, 2, 3
print(setallbitgivenrange(n, l, r)) 
  
# This code is contributed by Anant Agarwal. 

C#

// C# implementation to Set  
// bits in the given range 
using System; 
  
class GFG 
{ 
    // function to toggle bits  
    // in the given range 
    static int setallbitgivenrange(int n, int l, int r) 
    { 
          
        // calculating a number 'range'  
        // having set bits in the range  
        // from l to r and all other 
        // bits as 0 (or unset). 
        int range = (((1 << (l - 1)) - 1) ^  
                     ((1 << (r)) - 1)); 
      
        return (n | range); 
    } 
      
    // Driver code 
    static void Main() 
    { 
        int n = 17, l = 2, r = 3; 
        Console.Write(setallbitgivenrange(n, l, r)); 
    } 
      
} 
  
// This code is contributed by Sam007 

PHP

<?php 
// PHP implementation to Set  
// bits in the given range 
  
// function to toggle bits 
// in the given range 
function setallbitgivenrange($n, $l, $r) 
{ 
    // calculating a number 'range' 
    // having set bits in the range  
    // from l to r and all other 
    // bits as 0 (or unset). 
    $range = (((1 << ($l - 1)) - 1) ^  
                  ((1 << ($r)) - 1)); 
  
    return ($n | $range); 
} 
  
// Driver code 
$n = 17; 
$l = 2; 
$r = 3; 
echo setallbitgivenrange($n, $l, $r); 
  
// This code is contributed by Sam007 
?> 

Output :

This article is contributed by Devanshu Agarwal. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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