有一个画硬币程序，部分代码如下：
    for(int i=0;i<pDoc->m_n;i++)
    {   int y=200-10*i;
        CBrush mybrush(RGB(255,0,0));
        pDC->SelectObject(&mybrush);
        pDC->Ellipse(200,y,300,y-30);
        pDC->Ellipse(200,y-10,300,y-40);
    }
怎样使硬币个数为奇数、偶数时，硬币为两种不同的颜色？

for(int i=0;i<pDoc->m_n;i++)
    {   int y=200-10*i;
      if(pDoc->m_n%2==0)
       {
        CBrush mybrush(RGB(255,0,0));//偶数个的颜色
       }
      else{
         CBrush mybrush(RGB(0,255,0));//奇数个的颜色
       }
        pDC->SelectObject(&mybrush);
        pDC->Ellipse(200,y,300,y-30);
        pDC->Ellipse(200,y-10,300,y-40);
    }