【Leetcode】504. Base 7

public class Solution {
public String convertTo7(int num) {
String result = "";
int flag = 0;
if (num < 0) {
flag = 1;
num = Math.abs(num);
}
while(num >= 7) {
result = num % 7 + result;
num = num / 7;
}
result = num + result;
if (flag == 1)
result = "-" + result;
return result;
}
}