C#

David1987 wrote:

And make sure you reuse a single instance of Random,

// To generate as random numbers as possible, this variable must only
// be initialized once and then reused as much as possible.
Random rand = new Random();
/// <summary>
/// Generates a random 5 digit number that is always divisible by 5.
/// </summary>
/// <returns>Returns a random integer 5 digits long that is evenly divisible by 5.</returns>
private int GetDivBy5()
{

    // rnd.Next(minValue, maxValue) returns a random between minValue
    // and maxValue, inclusive. Use min/max values of 1000 and 9999 to
    // yield a random 4 digit number between 1000 and 9999 then multiply
    // by 10 to get a 5 digit number.  This number will always be
    // divisible by 5 but will always end in 0.
    int divBy5 = rand.Next(1000, 9999) * 10;

    // To get more random and double the possible result set, randomly
    // add on 5.  This will yield the total possible set of integers
    // between 10000 and 99995 that are divisible by 5.
    if (rand.NextDouble() < 0.5)
        return divBy5;
    else
        return divBy5 + 5;
}

private void button1_Click(object sender, EventArgs e)
{
    this.textBox1.Text = this.GetDivBy5().ToString("00000");

}

Chris Maunder wrote:

Everyone's a Legend in Their Own Lunchtime.

Chris Maunder wrote:

You've learned a lesson - whether you wished to or not

Chris Maunder wrote:

As to the others who felt it was easier to ridicule than to stop for a second and realise there was more to it, I apologise.

Michael A. Cochran wrote:

It's been a while since I worked with scientists but I seem to recall from my university days they can be somewhat socially lacking too.

Michael A. Cochran wrote:

it’s probably best to just take the "water off a ducks back" approach

// To generate as random numbers as possible, this variable must only 
// be initialized once and then reused as much as possible.
Random rand = new Random();

/// <summary>
/// Generates a random number between 0 and 99995 that is always divisible by 5.
/// </summary>
/// <returns>Returns a random integer up to 5 digits long that is evenly divisible by 5.</returns>
private int GetDivBy5()
{
   // Get a random number between 0 and 99999. 
   int divBy5 = rand.Next(0, 99999);
   // Subtract the remainder of (n/5) to make n divisible by 5.
   return divBy5 - (divBy5 % 5);
}

private void button1_Click(object sender, EventArgs e)
{
   this.textBox1.Text = this.GetDivBy5().ToString("00000");

}

int random= (rand()%18000)*5 + 10000

int random= (new Random().Next()%18000)*5 + 10000

int randomDivisibleByFive = random.Next(2000, 19999) * 5;

markymark82 wrote:

Having looked into it a little bit, I know I can send up to 5 emails concurrently using my smtp server before they start being throttled, and that I should be recycling the connections rather than creating and dropping them each time.