将小数点后四舍五入到小数点后两位

Question

I am trying to round decimal number upto two decimal places which is working perfectly. I am doing as below :

Math.Round(Amount, 2)

So, if I have Amount as 40000.4567 , I am getting 40000.46 which is exactly what I want. Now problem is I have decimal number like 40000.0000 , when I round it, the result is 40000 , and what I really want is 40000.00 . So round will always neglect trailing zeros.

To solve this problem, I have the option of converting it to string and use format , but I don't want to do that as that will be inefficient and I believe there must be some way to do it better.

I also tried something like

Decimal.Round(Amount, 2)

Now one way can be to check whether number contains anything in fractional part and use round function accordingly , but that is really bad way to do it. I can't use truncate as well due to obvious reasons of this being related to amount.

What is the way around?

Answer 1

It is rounding correctly but you fail to understand that the value is not the format. There is no difference between the two values, 40000 and 40000.00 , and you'll have a similar issue with something like 3.1 .

Simply use formatting to output whatever number you have to two decimal places, such as with:

Console.WriteLine(String.Format("{0:0.00}", value));

or:

Console.WriteLine(value.ToString("0.00"));

Answer 2

You are mixing two things - rounding and output formatting. In order to output a number in a format you want you can use function string.Format with required format, for example:

decimal number = 1234.567m;
string.Format("{0:#.00}", number);

You can read more about custom numeric format strings in MSDN

Answer 3

I think what you're looking for is displaying two decimals, even if they are zero. You can use string.Format for this (I've also combined it with Round):

Console.WriteLine(string.Format("{0:0.00}", Math.Round(Amount, 2));

Answer 4

for rounding decimal number you can use

decimal number=200.5555m;
number= Math.Round(number, 2);
string numString= string.Format("{0:0.00}", number);