C#——窗体程序，输入一个整数判断是否为质数

首先设计界面

编写如下代码

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 zh

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

 

        private void button1_Click(object sender, EventArgs e)

        {

            int zh =Convert .ToInt32( textBox1.Text);

            int t=(int)Math.Sqrt (zh);

            int i;

            for (i = 2; i <=t;i++ )

            {              

                if(zh % i==0)

                {

                    break;

                }

            }

            if (i <= t)

            {

                label2.Text = zh+"不是质数";

            }

            else 

            {

                label2.Text = zh+"是质数";

            }

            textBox1.Text = "";

        }

    }

}

 

 

运行结果