7 进制

给一个整数，返回其 7进制 的字符串表示

样例

样例 1:

输入: num = 100
输出: 202

样例 2:

输入: num = -7
输出: -10

注意事项

输入范围为[-1e7, 1e7] 。

 

class Solution {
public:
    /**
     * @param num: the given number
     * @return: The base 7 string representation
     */
    string convertToBase7(int num) {
        // Write your code here
        if(num == 0)
            return std::to_string(0);
        int tmpnum;
        if(num < 0)
            tmpnum = -num;
        else
            tmpnum = num;
        string ret;
        //cout<<tmpnum<<endl;
        while(tmpnum)
        {
            int yushu = tmpnum % 7;
            int shang = tmpnum / 7;
            ret = std::to_string(yushu)+ret;
            tmpnum = shang;
        }
        if(num < 0)
            ret = '-'+ret;
        return ret;
    }
};