Problem

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].

Pre analysis

Will use toString(base) function on top of number. A more language independent way would be to keep dividing by base and collecting quotient and remainder

Another Solution

var convertToBase7 = function(num) {
    if (num === 0) {
        return "0";
    }
    let sign = "";
    if (num < 0) {
        sign = "-";
        num = - num;
    }
    let base7 = "";
    while (num > 0) {
        base7 = num % 7 + base7;
        num = Math.floor(num / 7);
    }
    return sign + base7;
};