How do you check the length of a double in C++
<p>I'm using this code to check that a student number being entered is the correct number of digits. Is there a function like .length() that will work for the variable type double? Thanks!</p>

<pre><code>do {
    cout &lt;&lt; "Student's number: (Numeric only)";
    cin &gt;&gt; studentNumber;
    cin.ignore();
}
while (studentNumber.length() != 6);
</code></pre>
