undefined reference
<p>I'm unfamiliar to working in c++ under linux  so I have some issues, one of them is that after I write a class  and try to instantiate an object of that class  I get to following  error : "undefined reference to Constructor_of_that_class" . This happens for every class that I write , and it happens no matter where I try to do the instantiating, even if the code compiles without any problems . What is going wrong here and what I have to do to get over this error ? Because the project that I'm working wasn't created by me I suspect that it has to do something with some settings but I don't know which.</p>

<p>Edit (pasted from comment):</p>

<p>Well if I define a class this:</p>

<pre><code>class test {
    public:
        int a*;
        test( int* a)
}

class test {
    test::test( int* a)
        {
            this-&gt;a=a;
    }
}
</code></pre>

<p>and then in any class of those who where previously defined I use:</p>

<pre><code>test t =new test( anIntPointer);
</code></pre>

<p>then I get a undefined reference to <code>test::test(int*)</code>;</p>
