Correct way to precisely round decimals in C# [duplicate] - c#

This question already has answers here:
How do I make it round off instead of always round down?
(2 answers)
How to round a decimal up?
(6 answers)
Closed 5 months ago.
This is my code:
decimal test1 = 190.5m;
decimal test2 = 191.5m;
var testResult1 = Math.Round(test1, 0); // =190 It should be 191!!!!
var testResult2 = Math.Round(test2, 0); // =192 Correct.
Is there a way I could get the correct result? Maybe another library instead of System.Math?

This is by design. Albeit not what we have grown up with.
Find how you manage to round the way you expect here:
https://learn.microsoft.com/en-us/dotnet/api/system.midpointrounding?redirectedfrom=MSDN&view=net-6.0
For a bit more reading and background, have a browse through some of the answers here:
Why does .NET use banker's rounding as default?

Related

Is there a way to display 2 decimal places instead of automatically rounding? [duplicate]

This question already has answers here:
Why does integer division in C# return an integer and not a float?
(8 answers)
Closed 3 years ago.
I'm making a simple calculator in c# and and everything works well until I try dividing numbers that should give decimal places. How to display 2 decimal places in these cases?
I've tried putting #.## after .ToString.
{label1.Text = (divide / Convert.ToInt64(label1.Text)).ToString("#.##");}
I expect the output of 5/4 to be 1.25, but it is 1.
convert the number to float instead of int,
{label1.Text = ((float)divide / float.Parse(label1.Text)).ToString("n2");}

How to round a decimal number? [duplicate]

This question already has answers here:
Rounding a variable to two decimal places C# [duplicate]
(8 answers)
How do you round a number to two decimal places in C#?
(15 answers)
Closed 5 years ago.
I have a decimal number decimal n = 0.111111111m; and I want to change it to 0.112. How could I do this ?
You can use:
Math.Round(n, 3);
To always round up, you can use:
Math.Ceiling(n * 1000) / 1000;
According to this link
https://msdn.microsoft.com/en-us/library/6be1edhb(v=vs.110).aspx
You'll need to do something like Decimal.Round(n, 3);
However your initial approximation is not accurate

Math.Abs weird behaviour [duplicate]

This question already has answers here:
Double vs Decimal Rounding in C#
(2 answers)
Closed 7 years ago.
I am doing following equation but the result is not as expected
double dasdas = Math.Abs(3.2 - 1.9);
The result is
1.3000000000000003
However the correct result should be
1.3
What may be the reason of this?
c# 4.5.2
This is because you're using a double - which is a floating point. These by definition this cannot store the exact number.
You need to use Decimal.
Take at look at here and What Every Computer Scientist Should Read About Floating Point
Use decimal:
decimal dasdas = Math.Abs(3.2m - 1.9m);

Force two decimal places in C# [duplicate]

This question already has answers here:
Leave only two decimal places after the dot
(13 answers)
Closed 8 years ago.
I've this problem and can't find a solution.
This is super easy and i don't know why can't i find a solution.
Problem:
if a value returns for example "16.60", in c# i'll read "16.6", but i need 0 as well, because of paypal API, wich only accepts a value with no decimal numbers, or if it has to have decimal numbers the minimum and maximum must be 2.
So how can i make this?
i've tried this:
string value_f = "16,6";
decimal value_f_d = decimal.Parse(value_f);
value_f_d = (decimal)Math.Round(value_f_d, 2);
value_f = value_f_d.ToString("#.##");
value_f = value_f.Replace(',', '.');
i want this output: 16.60, but gives this: 16.6
string output = value_f_d.ToString("#.00", CultureInfo.InvariantCulture);
(using System.Globalization in your using declarations at the top)

Approximate percentage in ASP.net [duplicate]

This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
round up value C#
I want to approximate percentage in ASP.net, for example I had a percentage 72.72727272727% I want it to be approximated to 73%, how can I do that in ASP.net
lnPercentageRnd = Math.Round(72.72727272727, 0, MidpointRounding.AwayFromZero);
The AwayFromZero is important for natural rounding, because .Net defaults to Banker's Rounding.
It's not specific to ASP.NET, but .NET in general.
double d = .7272727272727;
string percent = d.ToString("p0"); // 73%
Percentage = Math.Round(Percentage)

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