$ - 문자열 보간

참고문서

https://docs.microsoft.com/ko-kr/dotnet/csharp/language-reference/tokens/interpolated

string name = "Mark"; var date = DateTime.Now; // Composite formatting: Console.WriteLine("Hello, {0}! Today is {1}, it's {2:HH:mm} now.", name, date.DayOfWeek, date); // String interpolation: Console.WriteLine($"Hello, {name}! Today is {date.DayOfWeek}, it's {date:HH:mm} now."); // Both calls produce the same output that is similar to: // Hello, Mark! Today is Wednesday, it's 19:40 now.