displaying random numbers

Question

Hello

I'm trying to design a code where one guess a number. I defined the range which number to display in my listbox. I started to write Random(1,10) but if I enter 11, it still writes in my listbox. How can I just write the number selected from my range, which is 1-10?

I'm quite lost here. Any ideas?

Thanks here is a part of my code:

     private void btnOk_Click(object sender, EventArgs e)
      {

        string yourNumber;
        yourNumber = textBox1.Text.Trim();

        int returnNumber = RandomNumber(1, 10);                 
        int.TryParse(textBox1.Text, out returnNumber);
        listBox1.Items.Add(returnNumber);            
      }

========= Additional question if I would like to display a range of number like for example 1-10, how could I do that: So for example, if the user will type 11 the program will not accept that.

I made something like this:

        int returnNumber = RandomNumber(1, 10);    

        string yourNumber;
        yourNumber = textBox1.Text.Trim();  


        if(Int32.TryParse(textBox1.Text>=1)) && (Int32.TryParse(textBox1.Text<=10));
        {
        listBox1.Items.Add(yourNumber);
        textBox1.Text = string.Empty;
        }

something is wrong in the program

==============

hello again thanks Nathaniel for the reply. But I tried this one:

int returnNumber=RandomNumber(1,10);
int counter=1;
int yourNumber;

Int32.TryParse(textBox1.Text.Trim(), out yourNumber);
if (yourNumber >=1 && yourNumber <= 10)
{
  listBox1.Items.Add(yourNumber);
}
else
{
  MessageBox.Show("Please enter a number between 1-10");
}

What I would like to do is design a program for guessing a number. So this is the first part.

====

Hi again, here is my final code: I would be happy if you could give feedback on how I can do it better. Thanks. I think the next thing I'll do is to limit the times the user types the input. That means, they can only guess the right number 3 times or 5 times. Not sure where to implement it

  namespace Guessing_Game
   {
  public partial class Form1 : Form
   {
    private static int randomNumber;
    private const int rangeNumberMin = 1;
    private const int rangeNumberMax = 10;

    public Form1()
    {
        InitializeComponent();
        randomNumber = GenerateNumber(rangeNumberMin, rangeNumberMax);
    }


    private int GenerateNumber(int min,int max)
    {
        Random random = new Random();
        return random.Next(min, max);
    }

    private void btnOk_Click(object sender, EventArgs e)
    {
        int yourNumber = 0;

        Int32.TryParse(textBox1.Text.Trim(), out yourNumber);

        if (yourNumber>= rangeNumberMin && yourNumber<=rangeNumberMax)
        {
            listBox1.Items.Add(yourNumber);
            if (yourNumber > randomNumber)
            {
                listBox2.Items.Add("No the Magic Number is lower than your number");
            }

            if (yourNumber < randomNumber)
            {
                listBox2.Items.Add("No, the Magic Number is higher than your number");
            }

            if(yourNumber==randomNumber)
            {
                listBox2.Items.Add("You guessed the Magic Number!");
                btnRestart.Enabled = true;
            }
        }
        else
        {
            MessageBox.Show("Please enter a number between " + rangeNumberMin + " to " + rangeNumberMax);
        }
    }

    private void btnRestart_Click(object sender, EventArgs e)
    {
        listBox2.Items.Clear();
        listBox1.Items.Clear();
        textBox1.Text = null;
        randomNumber = GenerateNumber(rangeNumberMin, rangeNumberMax);
        btnRestart.Enabled = false;
    }
}

Answer 1

The line:

int returnNunmber = RandomNumber(1, 10);

does nothing, because in the next line returnNumber is used as an output variable and will be whatever number is in textBox1. Remove the

int.TryParse(textBox1.Text, out returnNumber);

line and it will add a random number from 1 to 10 to your listbox.

EDIT:::: To answer you additional question, try:

private void btnOk_Click(object sender, EventArgs e)
  {
    string yourNumber;
    yourNumber = textBox1.Text.Trim();
    int returnNumber;    
    int.TryParse(textBox1.Text, out returnNumber);
    if( returnNumber < 1 || returnNumber > 10) {
      returnNumber = RandomNumber(1, 10);
    }
    listBox1.Items.Add(returnNumber);            
  }

Answer 2

Lets take that piece by piece:

int returnNumber = RandomNumber(1, 10);

There is no inbuilt RandomNumber function; note that with the Random class, the end value is exclusive, so for a number in a range, you'll need something like:

static readonly Random rand = new Random();
static int Random(int min, int max) {
    if(max < min) throw new ArgumentOutOfRangeException("max");
    lock(rand) {
        return rand.Next(min, max + 1);    
    }
}

However, you then throw away this value completely:

int.TryParse(textBox1.Text, out returnNumber);

The use of out means that the previous value of returnNumber is ignored completely. I'm not sure what your intent is, but it seems like you just want to check the value:

if(int.TryParse(textBox1.Text, out returnNumber)
      && returnNumber >= 1 && returnNumber <= 10)
{
    listBox1.Items.Add(returnNumber);
}

I've tried to look at the last example, but it really isn't clear what you are trying to do - can you clarify?

---

(edited after question edit and comments)

You would need a counter, which you increment for failed tries - something like:

using System;
using System.Drawing;
using System.Windows.Forms;
class MyForm : Form {
    Button btn;
    ListBox lst;
    TextBox tb;
    const int MaxTries = 3, MaxNumber = 10;
    int targetNumber, guessCount = 0;
    public MyForm() {
        targetNumber = new Random().Next(1, MaxNumber + 1);
        Text = "Guess a number";
        Icon = SystemIcons.Question;
        Controls.Add(lst = new ListBox {Dock=DockStyle.Fill});
        Controls.Add(btn = new Button {Text="Guess",Dock=DockStyle.Top});
        Controls.Add(tb = new TextBox {Dock=DockStyle.Top});
        btn.Click += btn_Click;
    }

    void  btn_Click(object sender, EventArgs e) {
        int userNumber;
        if (int.TryParse(tb.Text.Trim(), out userNumber)) {
            if (userNumber < 1 || userNumber > MaxNumber) {
                lst.Items.Add("Did I mention... between 1 and " + MaxNumber);
            } else {
                if (userNumber == targetNumber) {
                    lst.Items.Add("Well done! You guessed well");
                    btn.Enabled = false; // all done
                } else {
                    lst.Items.Add(targetNumber < userNumber
                        ? "Try a bit lower" : @"It is bigger than that");
                    if (++guessCount >= MaxTries) {
                        btn.Enabled = false;
                        lst.Items.Add("Oops, should have picked more wisely");
                    }
                }
            }
        } else {
            lst.Items.Add("Nice; now give me a number");
        }
    }
    [STAThread]
    static void Main() {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new MyForm());
    }
}

Answer 3

Some minor changes to your code, condensing a couple lines and adding the limit code, utilizing the list of guesses as the counter:

namespace Guessing_Game
{
   public partial class Form1 : Form
   {
        private static int randomNumber;
        private const int rangeNumberMin = 1;
        private const int rangeNumberMax = 10;
        private const int maxGuesses = 5;

        public Form1()
        {
            InitializeComponent();
            randomNumber = GenerateNumber(rangeNumberMin, rangeNumberMax);
        }


        private int GenerateNumber(int min,int max)
        {
            Random random = new Random();
            return random.Next(min, max);
        }

        private void btnOk_Click(object sender, EventArgs e)
        {
            int yourNumber = 0;

            if (Int32.TryParse(textBox1.Text.Trim(), out yourNumber) &&
               yourNumber>= rangeNumberMin && yourNumber<=rangeNumberMax)
            {

                listBox1.Items.Add(yourNumber);

                if (yourNumber > randomNumber)
                {
                    listBox2.Items.Add("No the Magic Number is lower than your number");
                }
                else if (yourNumber < randomNumber)
                {
                    listBox2.Items.Add("No, the Magic Number is higher than your number");
                }
                else
                {
                    listBox2.Items.Add("You guessed the Magic Number!");
                    textBox1.Enabled = false;
                    btnOk.Enable = false;
                    btnRestart.Enabled = true;
                }

                //Will stop on the 5th guess, but guards the case that there were more than 5 guesses
                if(listBox1.Items.Count >= maxGuesses && yourNumber != randomNumber)
                { 
                    listBox2.Items.Add("You are out of guesses!");
                    textBox1.Enabled = false;
                    btnOk.Enable = false;
                    btnRestart.Enabled = true;
                }
            }
            else
            {
                MessageBox.Show("Please enter a number between " + rangeNumberMin + " to " + rangeNumberMax);
            }
        }

        private void btnRestart_Click(object sender, EventArgs e)
        {
            listBox2.Items.Clear();
            listBox1.Items.Clear();
            textBox1.Text = null;
            randomNumber = GenerateNumber(rangeNumberMin, rangeNumberMax);
            btnRestart.Enabled = false;
            textBox1.Enabled = true;
            btnOk.Enable = true;

        }
    }
}

Editted to prevent the "You're out of guesses" message when the number is correctly guessed on the last guess.