Question

I’m creating a function where returns multiple of 10?

public static int NextInt(this Random rnd, int min = 0, int max = 1)
{
    if (rnd == null) throw new ArgumentNullException("rnd");
    if (min >= max) throw new InvalidOperationException();
    var delta = max - min;

    return min + (int)(rnd.NextDouble() * delta + min);
}

public static int MultipleOf10(this Random rnd, int minZeros = 1, 
    int maxZeros = 10)
{
    if (rnd == null) throw new ArgumentNullException("rnd");

    int pow = NextInt(rnd, minZeros, maxZeros);
    return (int)Math.Pow(10, pow);
}

I’ve got doubt about the these two functions. The first one must be similar like Next() and the another one must return multiples of ten.

Can you point me where I fix it? Because I’m almost sure of that.

Answer 1

I think the last line of NextInt() should be

return min + (int)(rnd.NextDouble() * delta);

Or:

return min + rnd.Next(delta);

Or even better:

return rnd.Next(min, max);

Also, you should keep in mind that the upper bounds of Random methods are exclusive. So, if rnd.NextInt(i, j) should return numbers between i and j inclusive, you probably want to change the computation of delta to:

int delta = max - min + 1;

or if you used the last option above, change it to:

return rnd.Next(min, max + 1);