float k = (float) dy/dx;
COLORREF color = RGB(255,0,0);
switch(k)
{
case (-1<k<0): DrawLine1(dc,x1,y1,x2,y2,color);
break;
case (k<=-1): DrawLine2(dc,x1,y1,x2,y2,color);
break;
//default:
}
//出错!
float k = (float) dy/dx;
COLORREF color = RGB(255,0,0);
switch(k)
{
case (-1<k<0): DrawLine1(dc,x1,y1,x2,y2,color);
break;
case (k<=-1): DrawLine2(dc,x1,y1,x2,y2,color);
break;
//default:
}
//出错!