breshenhams alogorithm

void ba(float x1,float y1,float x2,float y2,CDC* pdc,COLORREF color)
{
    float dx,dy,q,d,p0/*,m*/,l,m,p1,xk,yk,k=0,pk;
    dx=x2-x1;
    dy=y2-y1;
    /*m=dy/dx;*/
    q=2*dy;
    d=q-(2*dx);
    p0=q-dx;
    pk=p0;
    xk=x1;
    yk=y1;
    if(x1>x2)
    {
        l=x1;
    }
    else
    {
        l=x2;
    }
    if(y1>y2)
    {
        m=y1;
    }
    else
    {
        m=y2;
    }
    pdc->SetPixel(x1,y1,color);
    if(l>m)
    {
      while(xk<=l)
      {
          if(pk>0)
          {
              xk=xk+1;
              yk=yk+1;
              pk=pk+d;
              k++;
              pdc->SetPixel(xk,yk,color);
          }
          else
          {
              xk=xk+1;
              pk=pk+q;
              pdc->SetPixel(xk,yk,color);
              k++;
          }

      }
    }
    else
    {
        while(yk<=m)
      {
          if(pk>0)
          {
              xk=xk+1;
              yk=yk+1;
              pk=pk+d;
              k++;
              pdc->SetPixel(xk,yk,color);
          }
          else
          {
              xk=xk+1;
              pk=pk+q;
              k++;
              pdc->SetPixel(xk,yk,color);
          }
        }
    }

    }