Base 7

Given an integer, return its base 7 string representation.

Example 1:
Input: 100
Output: “202”
Example 2:
Input: -7
Output: “-10”
Note: The input will be in range of [-1e7, 1e7].

class Solution {public:    string convertToBase7(int num) {        if(num==0)            return "0";        int sign = (num>=0?1:-1);        num = abs(num);        string res;        while(num){            res = to_string(num%7) + res;            num/=7;        }        if(sign==-1)            res = '-' + res;        return res;    }};