将十进制数字四舍五入为固定数字和固定长度 [英] Rounding a decimal number to fixed number and fixed length

问题描述

我要舍入一个十进制数字，例如44.599521至 3 个数字

结果将是:44.6

但我想要的结果格式为:44.600

是否有任何用于所需结果的内置函数，或者我必须以编程方式进行.

谢谢.

I am Rounding a decimal number e.g. 44.599521 to 3 digits

result will be : 44.6

but i want result in the format : 44.600

is there any built in function for the required result or i have to do it programmatically.

Thanks.

推荐答案

如果您可以输出字符串，则对您有用.

If a string output is ok for you then this will work for you.

double num = 44.599521;<br />
CultureInfo ci = new CultureInfo("myCulture");<br />
ci.NumberFormat.NumberDecimalDigits=3;<br />
string s = num.ToString("N", ci);

首先，对不起.我不是c#程序员，但是前段时间我遇到了同样的问题，但是我没有找到内置函数.因此，我编写了自己的函数来执行此操作.这就是我所做的.

First of all, sorry. I am not a c# programer, but I had the same problem time ago and I found no built-in function. So I programmed my own function to do that. Here is what I did.

CString CMyDoc::RoundToNDecimals (double dValue, const int nDec)
{	double dTemp = 0, dFract = 0, dInt = 0, dRes = 0;
	// Operations to round up the nth decimal number if necessary
	dTemp = dValue*pow(10,nDec);
	dFract = modf (dTemp, &dInt);
	if (dFract >= 0.5)
		dInt++;
	dRes = dInt/pow(10,nDec);
        // Giving a variable string according to number and desired decimals as result
	CString szResult;
	szResult.Format ("%s%f", szResult, dRes);
	int nLarge = szResult.GetLength ();
	for (int i = 0; i < nLarge; i++)
	{	nCount++;
		CString cLetter = szResult.GetAt (i);
		if (cLetter == ".")
		{	nCount += nDec;
			break;
		}
	}
	// Truncate the string to be placed in the screen
	LPTSTR pStr = szResult.GetBufferSetLength (nCount);
	szResult.ReleaseBuffer ();

	return szResult;
;
}

希望对您有帮助

我认为没有办法以数字格式放入44.600，不考虑十进制数字右边的零.

Edit_2:以上所需语言的最佳答案...忘记这个

I hope it helps you

I think there is no way to put 44.600 in number format, zeros at the right in decimal numbers are not considered.

Edit_2: Best answer in required language above... forget this one

我更喜欢这种方式:

I prefer this way:

double val = 44.599521;
string formattedValue = String.Format("{0:#.000}", val);

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