Power of Two

Given an integer, write a function to determine if it is a power of two.

1、Mycode

class Solution {

public:

bool isPowerOfTwo(double n) {

int k = 1;

if (n <= 0)

{

return 0;

}

if(n == 1)

return 1;

while ((n / pow(2.0, k)) >= 1)

{

if ((n / pow(2.0, k) == 1))

return 1;

k++;

 

}

return 0;

}

};

2、 Reference Answer

class Solution {

public:

bool isPowerOfTwo(int n) {

return (n>0) && (!(n&(n-1)));

}

};

bool isPowerOfTwo(int n) {

int count = 0;

while (n > 0)

{

count+=(n&0x01);

n>>=1;

}

return count==1;

}