个人项目1：随机生成30道整数四则运算题

namespace 随机四则运算
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
       private void button2_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            
          double x = Convert.ToDouble(1);

        double y = Convert.ToDouble(99);

        double z = Convert.ToDouble(30);

        richTextBox1.Text = "";

        double [] a = new double [2*(int)z]; 

        Random r = new Random();

        for (int i = 0; i < 2*z; i++)

        {

            double  temp = r.Next((int)x,(int)y);

            a[i] = temp;

        }

        for (int i = 0; i < z; i++)

        {

            double w = i % 3;

            string c = "+";

            double d = a[i] + a[i + (int)z];

            if (d <= (int)y / 2)

                c = "*";

            if (d > (int)y / 2 && d <= (int)y)

                c = "+";

            if (d > (int)y && d <= (int)y * 1.5)

                c = "/";

            if (d > (int)y * 1.5 && d <= (int)y * 2 && a[i] > a[i + (int)z])

                c = "-";

            richTextBox1.AppendText(a[i].ToString() + (c) + a[i + (int)z].ToString() + ("=") + System.Environment.NewLine);

        }
    }

}

    }