Guess Higher or Lower.cpp

/** 
 * Forward declaration of guess API.
 * @param  num   your guess
 * @return 	     -1 if num is lower than the guess number
 *			      1 if num is higher than the guess number
 *               otherwise return 0
 * int guess(int num);
 */

class Solution {
public:
    int guessNumber(int n) {
        int low = 0, high = n;
        while(low <= high)
        {
            int mid = (high - low) / 2 + low;
            if(guess(mid) == 0)
                return mid;
            else if(guess(mid) == -1)
                high = mid - 1;
            else
                low = mid + 1;
        }
        return low;
    }
};