is power of 2

bool isPowerOfTwo(int n) {
    if (n <= 0) {
        return false;
    }
    return (n & (n - 1)) == 0;
}

Explanation:

1. bool isPowerOfTwo(int n): This function takes an integer n as input and returns a boolean value indicating whether n is a power of 2.

2. if (n <= 0) { return false; }: Checks if the input n is less than or equal to 0. If it is, the function returns false because non-positive numbers cannot be powers of 2.

3. (n & (n - 1)) == 0: This expression uses a bitwise AND operation between n and (n - 1). If the result of this operation is 0, it implies that n is a power of 2.

Explanation of (n & (n - 1)): - n - 1 decrements n by 1. - Bitwise AND (&) operation between n and n - 1 checks if there are no common set bits between n and n - 1. If n is a power of 2, it has only one bit set, and subtracting 1 sets all bits before this set bit. The result of the bitwise AND will be 0 in this case.

Example: Let's take n = 8 (which is a power of 2). - Binary representation of 8 is 1000. - n - 1 = 7, binary representation is 0111. - Bitwise AND operation between 8 and 7 (1000 & 0111) results in 0000, which equals 0. - Thus, 8 is a power of 2.

This function combines these steps to determine if the given integer is a power of 2 by utilizing bitwise operations.