or set the length to zero if
it does exist.</li>

<li><code class="keyword">w+</code>..Open the file for reading and
writing. Create the file if it doesn't exist, or set the length to
zero if it does exist.</li>

<li><code class="keyword">a</code>......Open the file for writing.
The file must already exist. Set the current location to the end of
the file.</li>

<li><code class="keyword">a+</code>...Open the file for writing.
The file does not exist, create it. Set the current location to the
end of the file