https://docs.microsoft.com/zh-cn/dotnet/standard/base-types/standard-numeric-format-strings
https://docs.microsoft.com/zh-cn/dotnet/standard/base-types/composite-formatting
https://docs.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/built-in-types-table
http://www.runoob.com/csharp/csharp-tutorial.html
https://docs.microsoft.com/zh-cn/dotnet/csharp/programming-guide/index
原文：https://www.cnblogs.com/Osea/p/11559292.html