程序代码：

关键部分代码：

public partial class frmStandCalculator : Form
    {
        public float number1 = 0;//存储前一个操作数;
        public bool flag = false;//标记单击了操作符没有，false为还未击操作符，ture为单击了操作符
        public char doflag = '+';//初始化操作符，单击了操作符时存储操作符号
        public bool pointflag = false;//标志是否单击了小数点;false为未击，true为已经单击;
        public float number2 = 0;//存储单击=号时TextNum的值
        public int n = 0;//记录是击了=键还是未击。
        public float M = 0;
        public string COPYM = "";

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 //开平方根：
        private void btnSqrt_Click(object sender, EventArgs e)
        {
            if (TxtNum.Text.Trim() != "")
            {
                float tempnumber = (float)Math.Sqrt(float.Parse(TxtNum.Text));//Math.Sqrt()结            //果为double型，所以要用float强制转换
                TxtNum.Text = tempnumber.ToString();
            }

            flag = true;
        }
        //百分号：
        private void btnPercent_Click(object sender, EventArgs e)
        {

        }
        //分数：
        private void btnFraction_Click(object sender, EventArgs e)
        {

        }
}

程序代码：

//参考：Site:<span style="color: #008000; text-decoration: underline;">http://apps.hi.baidu.com/share/detail/1192593[/color][/color]

private void Button_Percent_Click(object sender, EventArgs e)
        {
            number = Convert.ToString(Convert.ToDouble(TextBox.Text) / 100);
            TextBox.Text = number;
            number = "";
        }

private void Button_Reciprocal_Click(object sender, EventArgs e)
        {
            if (Convert.ToDouble(TextBox.Text) ==0)
            {
                this.TextBox.Text = "error";
            }
            else
            {
                number2 = Convert.ToDouble(TextBox.Text);
                number = "";
                TextBox.Text = Convert.ToString(1 / number2);
            }
    }

程序代码：

//百分号：
        private void btnPercent_Click(object sender, EventArgs e)
        {
            TxtNum.Text = (float.Parse(TxtNum.Text) / 100).ToString();

            pointflag = true;
        }


        //倒数：
        private void btnFraction_Click(object sender, EventArgs e)
        {
            TxtNum.Text = (1/float.Parse(TxtNum.Text)).ToString();

            pointflag = true;
        }