在单文档主菜单中增加“计算器”选项，实现点击“计算器”选项时弹出模态对话框，并在此对话框中实现整数计算器的功能。其中CE表示清0。-In a single document the main menu to add " calculator" option, to achieve click on the " calculator" option pop-up modal dialog box, and in this dialog box to achiev