Base7

//Given an integer, return its base 7 string representation.

class Solution {
    public String convertToBase7(int num) {
        StringBuilder str = new StringBuilder();
        StringBuilder reverse = new StringBuilder();

        if(num < 0)
        {
            reverse.append("-");
            num *= -1;
        }
        if(num == 0)
        {
            str.append("0");
        }
        while(num != 0)
        {
            str.append(num%7);
            num /= 7;
        }
        String temp = str.toString();
        for(int i = temp.length() - 1; i >=0; i--)
        {
            reverse.append(temp.charAt(i));
        }
        return reverse.toString();
    }
}