Structures as attributes
<p>These are the attributes of my class:</p>

<pre><code>    class Addition_Struct: public Addition {
    // attributes
    struct a {
        int element;
        struct a *next;
    };
    struct b {
        int element;
        struct b *next;
    };
    struct outcome {
        int element;
        struct outcome *next;
    };
    struct a a_data;
    struct b b_data;
    struct outcome outcome_data;
// methods
a convertToStackA(int); // everything is right with this line
</code></pre>

<p>How can I call them from inside the .cpp file? Using <code>this-&gt;a</code> syntax returns "type name is not allowed". Using <code>a*</code> as method's return value displays "Identifier is not allowed", and "Declaration is incompatible with...". </p>

<p>.cpp file:</p>

<pre><code>a* Addition_Struct::convertToStackA(int number)
{
   // identifier "a" is undefined, and declaration is incompatible
}
</code></pre>
