请教下VC++画坐标的程序：
在程序中，有这样几句话，请问什么意思：
    for(i=0; i<256; i+=10)
    {
        if(((i/10)&1) == 0)                              //  这里的语句表示什么意思？？？
        {
            pDC->MoveTo(i+30,280);
            pDC->LineTo(i+30,284);
        }
        else
        {
            pDC->MoveTo(i+30,280);
            pDC->LineTo(i+30,282);
        }
    }
    for(i=280; i>30; i-=40)                           //此处的for 语句什么意思？？？
    {
        if(((i/40)&1) == 1)
        {
            pDC->MoveTo(30,i);
            pDC->LineTo(26,i);
            str.Format(itoa((280-i)/8,temp,10));
            pDC->TextOut(5,i-10,str);      
        }
        else
        {
            pDC->MoveTo(30,i);
            pDC->LineTo(28,i);
           
        }
    }