VisualC++ function problems (and other)
<p>I have programmed in C++ a while, and I thought It would be fun to try to start with Visual C++ and make a calculator.</p>

<p>Okay, so I have designed at simple window, with two Textboxes, and one button that Adds the two boxes together.
I do know that I dont need a function for this, but I like to try things out, to learn them.
So when Im in the design view, I doubleclick on the button, to get to its code.
In the start of the code, I made two variables, and assigned a value to them.
Now I would like to call a function that takes two parameters and returns the added value.
Thats where it gets annoying, because I get this error:</p>

<pre><code> error C3861: 'addFunction': identifier not found
</code></pre>

<p>I also have another problem.
I have an if() to make sure that both textboxes have a value.
The if is like this:</p>

<pre><code>if(a &amp;&amp; b)
</code></pre>

<p>The compiler gives me this error:</p>

<pre><code>error C2676: binary '&amp;&amp;' : 'std::string' does not define this operator or a conversion to a type acceptable to the predefined operator
</code></pre>

<p>Yeah, one of the variables is a string, but it should still work, right?</p>

<p>I HOpe you can help me!</p>

<p><strong>EDIT</strong> 
I have solved these two problems, but now, some more occured.</p>

<p>The one error is complaining about this:</p>

<pre><code>textstring = DecryptedBox-&gt;Text;
</code></pre>

<p>And there is another error, occuring in the compiler log like 10 times</p>

<pre><code>C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xstring(707): could be 'std::basic_string&lt;_Elem,_Traits,_Ax&gt; &amp;std::basic_string&lt;_Elem,_Traits,_Ax&gt;::operator =(std::basic_string&lt;_Elem,_Traits,_Ax&gt; &amp;&amp;)'
1&gt;          with
1&gt;          [
1&gt;              _Elem=char,
1&gt;              _Traits=std::char_traits&lt;char&gt;,
1&gt;              _Ax=std::allocator&lt;char&gt;
1&gt;          ]
</code></pre>

<p>What does it mean?</p>
