C++ input with WINAPI

Question

Ok, I am making a simple camera movement program in directx9. I take the input from the messages like so:

        LRESULT CALLBACK WindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
    {
        switch (uMsg)
        {
        case WM_KEYDOWN:
            switch (wParam & 0x7F)
            {
                case 'W':
                    WDown = true;
                case 'A':
                    ADown = true;
                case 'S':
                    SDown = true;
                case 'D':
                    DDown = true;
            }
        case WM_KEYUP:
            switch (wParam & 0x7F)
            {

                    case 'W':
                        WDown = false;
                    case 'A':
                        ADown = false;
                    case 'S':
                        SDown = false;
                    case 'D':
                        DDown = false;
               }
           }
    }

    // Render Frame code:

    void Renderer::RenderOneFrame(bool w, bool a, bool s, bool d)
    {
    // Check Input
        if(w)
            m_camera.MoveForward(1);
        else if(a)
            m_camera.Strafe(-1);
        else if(s)
            m_camera.MoveForward(-1);
        else if(d)
            m_camera.Strafe(1);
    }

Super simple right? I left out a lot of other code though, but it doesn't mess with these booleans at all, so they shouldn't be needed. Well, now here is the catch. It works perfectly if I use this code. Forward is forward, Right is right, Left is left, Back is back.

Problem is, I want to be able to move diagonally. So, obvious answer is get rid of else right? Well I do.

BUT, the program goes to chaos! Forward doesn't go forward! It doesn't do a thing! Left goes Backwards and Backwards goes backwards to the right! The only one that works right is right! Which is coincidentally the last input checked! But I have been pressing 1 key at a time, but they still are broken! What happened? Did I break visual studio? Is this program leaking into another dimension? What is going on?!?

Answer 1

Did you forget the "break" on switch case?

Example:

LRESULT CALLBACK WindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    switch (uMsg)
    {
    case WM_KEYDOWN:
        switch (wParam & 0x7F)
        {
            case 'W':
                WDown = true;
                break;
            case 'A':
                ADown = true;
                break;
            case 'S':
                SDown = true;
                break;
            case 'D':
                DDown = true;
                break;
        }
        break;
    case WM_KEYUP:
        switch (wParam & 0x7F)
        {

                case 'W':
                    WDown = false;
                    break;
                case 'A':
                    ADown = false;
                    break;
                case 'S':
                    SDown = false;
                    break;
                case 'D':
                    DDown = false;
                    break;
           }
       }
       break;
}

// Render Frame code:

void Renderer::RenderOneFrame(bool w, bool a, bool s, bool d)
{
// Check Input
    if(w)
        m_camera.MoveForward(1);
    if(a)
        m_camera.Strafe(-1);
    if(s)
        m_camera.MoveForward(-1);
    if(d)
        m_camera.Strafe(1);
}