编一个 华氏温度与摄氏温度转换的程序 用VB 怎么办

Private Sub cmdOK_Click()If txtH.Text = "" And txtS.Text = "" ThenMsgBox "请输入温度！"ElseIf opHtoS.Value = True ThentxtS.Text = (Val(txtH.Text) - 32) / 1.8ElseIf opStoH.Value = True ThentxtH.Text = Val(txtS.Text) * 1.8 + 32En