round up given number in c#

I want round up given numbers in c#

Ex:

round(25)=50
round(250) = 500 
round(725) = 1000
round(1200) = 1500
round(7125) =  7500  
round(855开发者_运维百科0) = 9000

---

Most of your data suggests that you want to round up to the nearest multiple of 500. This would be done by

int round(int input)
{
    return (int)(500 * Math.Ceiling(input / 500.0));
}

The rounding of 25 to 50 will not work, though.

Another guess would be that you want your rounding to depend on the size of the number being rounded. The following function would round 25 to 50, 250 to 500, 0.025 to 0.05, and 2500 to 5000. Maybe you can work from there.

double round(double input)
{
    double scale = Math.Floor(Math.Log10(input));
    double step = 5 * Math.Pow(10, scale);
    return step * Math.Ceiling(input/step);
}

---

Depending on what you need, this could be a nice, reusable solution.

    static int RoundUpWeird(int rawNr)
    {
        if (rawNr < 100 && rawNr > -100)
            return RoundUpToNext50(rawNr);
        else
            return RoundUpToNext500(rawNr);
    }

    static int RoundUpToNext50(int rawNr)
    {
        return RoundUpToNext(rawNr, 50);
    }


    static int RoundUpToNext500(int rawNr)
    {
        return RoundUpToNext(rawNr, 500);
    }

    static int RoundUpToNext(int rawNr, int next)
    {
        int result;
        int remainder;
        if ((remainder = rawNr % next) != 0)
        {
            if (rawNr >= 0)
                result = RoundPositiveToNext(rawNr, next, remainder);
            else
                result = RoundNegativeToNext(rawNr, remainder);
            if (result < rawNr)
                throw new OverflowException("round(Number) > Int.MaxValue!");
            return result;
        }
        return rawNr;
    }

    private static int RoundNegativeToNext(int rawNr, int remainder)
    {
        return rawNr - remainder;
    }

    private static int RoundPositiveToNext(int rawNr, int next, int remainder)
    {
        return rawNr + next - remainder;
    }

---

This code should work according to the rules I can gather:

public static double Round(double val)
{
    int baseNum = val <= 100 ? 100 : 1000;
    double factor = 0.5;
    double v = val / baseNum;
    var res = Math.Ceiling(v / factor) / (1 / factor) * baseNum;
    return res;
}

---

This should work. And also for numbers greater than those you wrote:

int round(int value)
{
   int i = 1;
   while (value > i)
   {
      i *= 10;
   }

   return (int)(0.05 * i * Math.Ceiling(value / (0.05 * i)));
}