How to Find the number zero in decimal part where add no value to the number and remove that part

I am using the following code to convert cm to the meter.

 public static double? ConvertCmToM(double? cm)
        {
            return cm.Value * 0.01;
            
        }

When I input the number 8.8 output giving as

0.08800000000000001m

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But I want to stop in the index where zero adds no value in the decimal part. In this case I want to display the value as

0.088m

This is already done in major converter websites. when you type the cm to m converter on google those sites will appear. How do they do it?

I took the same sample and put in their sites and this is how they show.

> 0.088m

I cannot blindly substring the value after converting to a string as the zero part will appear in 5th or 6th element.
That also handled in those sites.

This is a double data type. the letter "m" concat at the last minute. How to acehive this?

>Solution :

I would use decimal instead of double then:

public static decimal? ConvertCmToM(decimal? cm)
{
    if(cm == null) return null;
    return Decimal.Multiply(cm.Value, 0.01m);
}

static void Main()
{
    Console.Write(ConvertCmToM(8.8m)); // 0.088
}

decimal vs double! – Which one should I use and when?