504. Base 7

Given an integer, return its base 7 string representation.

Example 1:

Input: 100Output: "202"

Example 2:

Input: -7Output: "-10"

Note: The input will be in range of [-1e7, 1e7].

class Solution {public:    string convertToBase7(int num) {        if(num == 0){            return "0";        }        string res;                int abs_num = abs(num);        while(abs_num > 0){            string temp = to_string(abs_num % 7);            res = temp + res;            abs_num /= 7;        }        return num >= 0 ? res : '-' + res;    }};