C#——设计Windows程序，输入x,输出y值。

设计界面：

编写代码

 

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 x

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

 

        private void button1_Click(object sender, EventArgs e)

        {

            try

            {

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

                int y = 0;

                if (x >= 0 & x < 10)

                {

                    y = 1 - x * 2;

                }

                else if (x >= 10 & x < 20)

                {

                    y = x;

                }

                else if (x >= 20 & x < 30)

                {

                    y = 1 + x * 2;

                }

                else

                {

                    MessageBox.Show("请输入0-30之间的数字");

                }

                label2.Text = "y的值为：" + Convert.ToString(y);

            }

            catch 

            {

                MessageBox.Show("请输入数字x");

            }

        }

    }

}

 

运行结果：