如果Dx=0,Dy=-34,执行以下代码后,HDFWJ的值是( )。 If Dx > 0 And Dy > 0 Then HDFWJ = Atn(Abs(Dy / Dx)) ElseIf Dx < 0 And Dy > 0 Then HDFWJ = Pi - Atn(Abs(Dy / Dx)) ElseIf Dx < 0 And Dy < 0 Then HDFWJ = Pi + Atn(Abs(Dy / Dx)) ElseIf Dx > 0 And Dy < 0 Then HDFWJ = 2 * Pi - Atn(Abs(Dy / Dx)) ElseIf Dx > 0 And Dy = 0 Then HDFWJ = 0 ElseIf Dx < 0 And Dy = 0 Then HDFWJ = Pi ElseIf Dx = 0 And Dy > 0 Then HDFWJ = Pi / 2 ElseIf Dx = 0 And Dy < 0 Then HDFWJ = 3 * Pi / 2 ElseIf Dx = 0 And Dy = 0 Then HDFWJ = 0 End If