How to check if a number is a power of 2 in C#?

A power of 2 is a number of the form 2n where n is an integer

The result of exponentiation with number two as the base and integer n as the exponent.

Example 1

 Live Demo

class Program {
   static void Main() {
      Console.WriteLine(IsPowerOfTwo(9223372036854775809));
      Console.WriteLine(IsPowerOfTwo(4));
      Console.ReadLine();
   }
   static bool IsPowerOfTwo(ulong x) {
      return x > 0 && (x & (x - 1)) == 0;
   }
}

Output

False
True

Example 2

 Live Demo

class Program {
   static void Main() {
      Console.WriteLine(IsPowerOfTwo(9223372036854775809));
      Console.WriteLine(IsPowerOfTwo(4));
      Console.ReadLine();
   }
   static bool IsPowerOfTwo(ulong n) {
      if (n == 0)
         return false;
      while (n != 1) {
         if (n % 2 != 0)
            return false;
         n = n / 2;
      }
      return true;
   }
}

Output

False
True

Nizamuddin Siddiqui

Published on 08-Aug-2020 08:46:50

• Related Questions & Answers
• Check if given number is a power of d where d is a power of 2 in Python
• Check if a number is a power of another number in C++
• Check if a number is power of 8 or not in C++
• Number of pairs whose sum is a power of 2 in C++
• Write a C# program to check if a number is divisible by 2
• Check if a number is power of k using base changing methods in C++
• Nearest power 2 of a number - JavaScript
• Check if a number can be expressed as power in C++
• Compute modulus division by a power-of-2-number in C#
• Check if a number can be expressed as 2^x + 2^y in C++
• Checking if a number is a valid power of 4 in JavaScript
• Check if a number is Palindrome in C++
• Check if a number is Bleak in C++
• Check if a number is a Mystery Numbers in C++
• Check if a number is a Trojan Numbers in C++