Math function to round up the values to .0 or .5

Question

How can I round numbers up to the nearest whole or to the nearest half?

For Example:

> 23.15 --> 23.5
> 23.56 --> 24.0

The rounding functions I know about are floor and ceil, but those only round to the nearest integer.

Answer 1

You want to round up, to a multiple of 0.5? Am I understanding that correctly?

double RoundUpToPointFive(double d)
{
    return Math.Ceiling(d * 2) / 2;
}