How to truncate decimal in X decimal places?

Question

How to truncate decimal in X decimal places?

Asked 7 years, 3 months ago

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0

I am using the following code, but when sending ex:'10.100' to 2 houses it returns '10.1', but it should be '10.10'

    public decimal TruncarDecimal(decimal value, int decimalPlaces)
    {
        decimal integralValue = Math.Truncate(value);

        decimal fraction = value - integralValue;

        decimal factor = (decimal)Math.Pow(10, decimalPlaces);

        decimal truncatedFraction = Math.Truncate(fraction * factor) / factor;

        decimal result = integralValue + truncatedFraction;

        return result;
    }

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– Maniero

2017/10/07 at 16:49

2 answers

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by Maniero • **444,682** points · Answer 1 · 2017-09-19T15:02:21+00:00

3

Supports yes, see the documentation. There you have without the parameter of decimals, with this information and even as the rounding criterion should be.

Math.Round(valorDecimal, 2);

If what you want is not rounding then do the Truncate() climbing:

Math.Truncate(100 * valorDecimal) / 100;

I put in the Github for future reference.

But this is basically what’s in the question.

But I can’t round, the round changes the value

– Bruno Rodrigues

2017/09/19 at 17:03
I answered what was in the question, now you say you can not do what you asked to do. I think the question is not clear then.

– Maniero

2017/09/19 at 17:19
I quoted the Round example that I can choose decimal places, but it would need to be the truncate, so I could choose the houses, When I use Math.Truncate(decimal), the parameter is only the value.

– Bruno Rodrigues

2017/09/19 at 17:23
The Truncate() also changes the value, you need to decide if you want to change the value or not. On the other hand if it is the Truncate() who wants to use, use it, do not know the purpose of the question in this case.

– Maniero

2017/09/19 at 17:33
I will try to summarize for you understand, I do multiplications and the results give ex: 1,64857, I need to return the value with X decimal places depending on each case, I will not say more about truncate or Math, I need to do this.

– Bruno Rodrigues

2017/09/19 at 17:39
If you don’t make it clear what you want, you can’t answer it the way you want. I’ve already coclqoeui two possibilities, if neither of the two solves, I think and you can’t tell what’s wrong with these solutions. the problem is that you do not know what you want to do. There is no way to give an answer, when you do not know what the question is. What you asked was answered, if you wanted to ask something else, you would need to make it clear.

– Maniero

2017/09/19 at 17:41
Let’s go continue this discussion in chat.

– Bruno Rodrigues

2017/09/19 at 17:42

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by Eder Nascimento • 72 points · Answer 2 · 2017-09-19T15:03:47+00:00

Try using the

Math.Truncate

for example:

using System;

class Program
{
    static void Main()
    {
        decimal a = 1.223M;
        double b = 2.913;

        a = Math.Truncate(a);
        b = Math.Truncate(b);

        Console.WriteLine(a);
        Console.WriteLine(b);
    }
}

Exits:

1
2

Now if you need to display the value with two decimal places use the code:

decimalVar.ToString("#.##");

More information on Math.Truncate see this link: https://social.msdn.microsoft.com/Forums/pt-BR/fbf78553-93ab-4a96-9e1b-39160df5d216/truncar-variavel-para-apenas-2-decimais?forum=vscsharppt