Round to next greater multiple of 8

Given an unsigned integer x. Round it up to the next greater multiple of 8 using bitwise operations only.

Examples:

Input : 35
Output : 40

Input : 64
Output : 64 (As 64 is already a multiple of 8. So, no modification is done.)

Solution 1: We first add 7 and get a number x + 7, then we use the technique to find next smaller multiple of 8 for (x+7). For example, if x = 12, we add 7 to get 19. Now we find next smaller multiple of 19, which is 16.

Solution 2: An efficient approach to solve this problem using bitwise AND operation is:
x = (x + 7) &(-8)
This will round up x to the next greater multiple of 8.

C++

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// CPP program to find smallest greater multiple
// of 8 for a given number
#include <bits/stdc++.h>
using namespace std;
  
// Returns next greater multiple of 8
int RoundUp(int& x)
{
    return ((x + 7) & (-8));
}
  
int main()
{
    int x = 39;
    cout << RoundUp(x);
    return 0;
}

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Java














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// Java program to find smallest  


// greater multiple of 8 for  


// a given number  


import java.util.*; 


import java.lang.*; 


  


// Returns next greater  


// multiple of 8  


class GFG  


{ 


    static int RoundUp(int x)  


    {  


        return ((x + 7) & (-8));  


    }  


      


    // Driver Code 


    public static void main(String args[])  


    {  


        int x = 39;  


        System.out.println(RoundUp(x)); 


    }  


} 


  


// This code is contributed  


// by Akanksha Rai(Abby_akku) 



















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Python 3














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# Python 3 program to find  


# smallest greater multiple  


# of 8 for a given number 


  


# Returns next greater 


# multiple of 8 


def RoundUp(x): 


    return ((x + 7) & (-8)) 


      


# Driver Code 


x = 39


print(RoundUp(x)) 


  


# This code is contributed  


# by prerna saini 



















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C#














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// C# program to find smallest  


// greater multiple of 8 for  


// a given number  


using System;  


  


// Returns next greater  


// multiple of 8  


class GFG  


{ 


    static int RoundUp(int x)  


    {  


        return ((x + 7) & (-8));  


    }  


      


    // Driver Code 


    public static void Main()  


    {  


        int x = 39;  


        Console.WriteLine(RoundUp(x)); 


    }  


} 


  


// This code is contributed  


// by SoumikMondal 



















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PHP














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<?php 


// PHP program to find smallest greater  


// multiple of 8 for a given number 


  


// Returns next greater 


// multiple of 8 


function RoundUp($x) 


{ 


    return (($x + 7) & (-8)); 


} 


  


// Driver Code 


$x = 39; 


echo RoundUp($x); 


  


// This code is contributed  


// by Akanksha Rai(Abby_akku) 


?> 



















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Output:


40





Time Complexity: O(1)

Space Complexity: O(1)


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