Round to 25, 50, 75, 100

Question

I\'m not a Math person so I\'m having a hard time to come up with a calculation to round the decimals to 25, 50, 75 and 100. And this will not be the typical round off because t

Answer 1

I suggest using types without floating point.

decimal RoundNearestCents(decimal price) {
    // no problems with floating point as all calculations are exact
    return Math.Floor((price * 100 + 24) / 25) * 25 / 100;
}

-- Why is your price string?

-- Because it's coming from a textbox.

I assume your textbox should support limiting your input to decimal numbers with at most 2 decimal places. So its value will be decimal already. However I don't know what is your application type. If you still want to accept string then consider using decimal.TryParse method to convert it to decimal.

Answer 2

public float RoundNearestCents(double d)
{
  return (double)(Math.Ceiling(d * 4)) / 4;
}

Answer 3

My code may not be the best out there, but it will work. In your function create a float and an int like so.

public float RoundNearestCents(String price)
{
    float srp = float.Parse(price);
    int srp1 = Int32.Parse(price);
    if((srp-srp1)>=0.5) 
        srp1++;
    else 
        return srp1;
    return srp1;
}

The int would truncate out the decimal part, which is like flooring the price.

Answer 4

I would use something like this:

float RoundNearestCents(float price)
    {
    price*=(100/25.0); // now fractions are going away
    if (price-floor(price)>=0.5) price++; // round up if fraction above 0.5
    return floor(price)*(25.0/100.0); // cut of the fraction and restore original range
    }

Answer 5

This is one way:

public decimal RoundNearestCents(decimal price)
{
    decimal srp = price * 100;
    decimal m = srp % 25;
    srp = srp - m + (m > 0 ? 25 : 0);
    return srp / 100;
}