二柱子在线答题

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;

namespace 软工
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {

            int[] ans = new int[30];
            int [] number = new int[60];
            Random random = new Random();
            
            for(int i=0;i<60;i++)
            {
                number[i] = random.Next(0, 100);
            }
            for (int i = 0; i < 30; i++)
            {
                int a = random.Next(0, 3);
                if (number[i + 30] != 0 && (number[i] % number[i + 30]) == 0)
                {
                    textBox4.AppendText(number[i] + "/" + number[i + 30] + "=" + " ");
                    ans[i] = number[i] / number[i + 30];
                    textBox1.AppendText(Convert.ToString(ans[i]) + " ");
                }
                else if (a == 1)
                {
                    textBox4.AppendText(number[i] + "-" + number[i + 30] + "=" + " ");
                    ans[i] = number[i] - number[i + 30];
                    textBox1.AppendText(Convert.ToString(ans[i]) + " ");
                }
                else if (a == 0)
                {
                    textBox4.AppendText(number[i] + "*" + number[i + 30] + "=" + " ");
                    ans[i] = number[i] * number[i + 30];
                    textBox1.AppendText(Convert.ToString(ans[i]) + " ");
                }
                else
                {
                    textBox4.AppendText(number[i] + "+" + number[i + 30] + "=" + " ");
                    ans[i] = number[i] + number[i + 30];
                    textBox1.AppendText(Convert.ToString(ans[i]) + " ");
                }
            }
            
        }

        private void button2_Click(object sender, EventArgs e)
        {
            textBox1.Visible = true;
            string s = textBox5.Text;
            string[] ss = s.Split(new char[1] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
            string a = textBox1.Text;
            string[] ans = a.Split(new char[1] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
            if (ss.Length < 30)
            {
                MessageBox.Show("未答完题！");
                return;
            }
            for (int i = 0; i < 30; i++)
            {
                if (ss[i] == null)
                {
                    MessageBox.Show("有空答案");
                    return;
                }
               
            }
            for (int i = 0; i < 30; i++)
            {
                if (Convert.ToInt32 ( ss[i]) ==Convert.ToInt32 (ans[i]))
                    textBox6.AppendText("正确" + " ");
                if (Convert.ToInt32(ss[i]) != Convert.ToInt32(ans[i]))
                    textBox6.AppendText("错误" + " ");
            }
        }

        private void textBox1_TextChanged_1(object sender, EventArgs e)
        {

        }

        private void button4_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            
            
            
            SaveFileDialog sfile = new SaveFileDialog();
            sfile.Filter = "错题本|*.text";
            if(sfile.ShowDialog()==DialogResult.OK )
            {
                StreamWriter sw = new StreamWriter(sfile.FileName);
                sw.WriteLine(textBox4.Text);
                sw.Close();