using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

namespace 平方计算器

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        private void button1_Click(object sender, EventArgs e)

        {

            double a = double.Parse(textBox1.Text);

            double retrun = Math.Sqrt(a);

            label1.Text = a + "的平方跟是：" + retrun.ToString() ;//ToString转换字符串。

        }

        private void Form1_Load(object sender, EventArgs e)

        {

        }

    }

}