英文:
Using NAN as not defined value
问题
我正在开发一个C#项目，用于向用户显示一个双精度值。如果这个值未定义，我将显示一个空字符串。当值被定义时，它将大于或等于零。为了处理未定义的情况，我考虑是否可以定义一个超出范围的值，例如-1来表示未定义，或者将该值包装在一个具有布尔定义标志的类中。然后我想，为什么不直接使用Double.NAN来表示值未定义，然后使用Double.IsNAN来检查未定义的值呢？我认为这会起作用，但感觉有点不对。使用Double.NAN来表示未定义的值是一个好主意吗？
英文:
I am working on a CSharp project that displays a double value to the user. This value may not be defined in which case I will display an empty string. When the value is defined it will be greater than or equal to zero. To handle the not defined case, I thought I could define an out of range value, e.g. -1 to represent not defined or wrap the value in a class that has a boolean defined flag. Then I thought, why not just use Double.NAN to signify the value is not defined and Double.IsNAN to check for undefined values. I think this will work, but it just feels a bit wrong. Is it a good idea to use Double.NAN to represent an undefined value?
答案1
得分: 2
你可以使用现有包装器 Nullable<double> 或 double?
double? d;
if (d.HasValue)
Console.WriteLine($"{d.Value}");
Console.WriteLine($"{d.GetValueOrDefault(0)}"); // 如果值未定义，则会打印0
我认为这更合适，因为double.NaN 用于数学运算中的未定义结果情况。
英文:
you can use existing wrapper Nullable<double> or double?
double? d;
if (d.HasValue)
Console.WriteLine($"{d.Value}");
Console.WriteLine($"{d.GetValueOrDefault(0)}"); // this will print 0 if value was not defined
It better suits I suppose since double.NaN is for result undefined cases for math operations
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