<p>Given an integer <code>num</code>, return <em>a string of its <strong>base 7</strong> representation</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<pre><strong>Input:</strong> num = 100
<strong>Output:</strong> "202"
</pre><p><strong class="example">Example 2:</strong></p>
<pre><strong>Input:</strong> num = -7
<strong>Output:</strong> "-10"
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>-10<sup>7</sup> &lt;= num &lt;= 10<sup>7</sup></code></li>
</ul>

class Solution {
public:
    string convertToBase7(int num) {
       string ans = "";
       bool negative = false;
       if(num < 0){
            negative = true;
            num = -num;
       }
       do{
            ans += num%7 + '0';
            num = num/7; 
       } while(num);
       reverse(ans.begin(), ans.end());
       if (negative) ans = "-" + ans;
       return ans;
    }
};
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