C++ compile order
<p>[Actor.h]</p>

<pre><code>#include "../PathEngine/Actor.h"
namespace FightEngine
{
    class Actor
        :public PathEngine::Actor
    {
    private:
        .....
    public:
        Actor();
        ~Actor();
        void SetPosition(int x, int y);
    };
}
</code></pre>

<p>[Actor.cpp]</p>

<pre><code>#include "Actor.h"
namespace FightEngine
{
    Actor::Actor()
        :PathEngine::Actor()
    {
        do something
    }
    Actor::~Actor()
    {

    }
    void Actor::SetPosition(int x, int y)
    {
        do something
    }
}
</code></pre>

<p>[main.cpp]</p>

<pre><code>FightEngine::Actor* actor = new FightEngine::Actor();
actor-&gt;SetPosition(400,200);
</code></pre>

<p>it's give me some </p>

<p>></p>

<blockquote>
  <p>error LNK2019: unresolved external symbol....</p>
</blockquote>

<p>I guess that Actor::SetPosition(x,y), Actor::Actor(), declared but aren't defined. BUT I ACTUALLY DEFINED IT in Actor.cpp. the problem is compiler don't compile Actor.cpp, i don't know why.</p>
