title: How to find the length(number of digits)of a long in C?
body: <p>This is the code prompting the user for input</p>
  
  <pre><code>#include &lt;stdio.h&gt;
  #include &lt;cs50.h&gt;
  
  //prompt user for number
  
  int main(void)
  {
        long number = get_long("Enter card number: "); 
  }
  </code></pre>