C#编写的windows计算器-源代码

C#编写的windows计算器-源代码(34)         //获取操作符运事件
        private void btn_Oper(object obj,EventArgs ea)
        {
            Button tmp1=(Button)obj;
            strOper=tmp1.Text;
            switch (strOper)
            {
                case "/":       //除法运算
                    if(opt!=NULL&&opt!=DIV)
                    {
                        calc();
                    }
                    opt = DIV;
                    if (num != 0)  //判断操作数的个数,如果两个就做二元运算
                    {
                        if (tmp != 0)
                            res = res / tmp;
                    }