TheAlgorithms-C-Plus-Plus/math/power_of_two.cpp

/**
 * @file power_of_two.cpp
 * @brief Implementation to check whether a number is a power of 2 or not.
 *
 * @details
 * This algorithm uses bit manipulation to check if a number is a power of 2 or not.
 *
 * ### Algorithm
 * Let the input number be n, then the bitwise and between n and n-1 will let us know 
 * whether the number is power of 2 or not
 * 
 * For Example,
 * If N= 32 then N-1 is 31, if we perform bitwise and of these two numbers then
 * the result will be zero, which indicates that it is the power of 2
 * If N=23 then N-1 is 22, if we perform bitwise and of these two numbers then
 * the result will not be zero , which indicates that it is not the power of 2
 * \note This implementation is better than naive recursive or iterative approach. 
 * 
 * @author [Neha Hasija](https://github.com/neha-hasija17)
 */
 
#include <iostream>
/**
 * Function to test above algorithm
 */
void power_of_two(int n){
	 /**
             * This function finds whether a number is power of 2 or not
             * @param n value for which we want to check
             * prints the result, as "Yes, the number n is a power of 2" or 
             * "No, the number is not a power of 2" without quotes
           */     
        /// result stores the 
        /// bitwise and of n and n-1
        int result = n & (n-1);
        if(result==0) 
        
        std::cout<<"Yes, the number "<<n<<" is a power of 2";
        else 
        std::cout<<"No, the number "<<n<<" is not a power of 2";
             
}

/**
 * @brief Main function
 * @returns 0 on exit
 */
int main() {
    int n;
    ///n stores the input from the user
    std::cout<<"enter a number "<<std::endl;
    std::cin>>n;
    ///function call with @param n
    power_of_two(n);
    return 0;
}