How to get the size of the used space in an array? (NOT sizeof); c++
<pre><code>#include&lt;iostream&gt;
using namespace std;

int main()
{
    char arr[200];
    while(1) {
        cin &gt;&gt; arr;
        int i = sizeof(arr);
        cout &lt;&lt; "The arr input is "&lt;&lt; arr 
             &lt;&lt; " and the size of the array is "&lt;&lt; i &lt;&lt; endl;
    }
    return 0;
}
</code></pre>

<p>For the input of 34,
This code outputs :The arr input is 34 and the size of the array is 200 </p>

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<p>while I want it to get the size of the used space of the array . So for The last input i want it to output :The arr input is 34 and the size of the array is 2</p>

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<p>Can someone tell me how?</p>
