public static void Main()
int nY, nMM, nD, nH, nM, nSec;
DateTime yesterday = DateTime.Now.AddDays(-1);
string test = "jacuzzis.dat.20191210090116";
string[] testSplit = test.Split('.');
string numString = testSplit[2];
Int32.TryParse(numString.Substring(0, 4), out nY);
Int32.TryParse(numString.Substring(4, 2), out nMM);
Int32.TryParse(numString.Substring(6, 2), out nD);
Int32.TryParse(numString.Substring(8, 2), out nH);
Int32.TryParse(numString.Substring(10, 2), out nM);
Int32.TryParse(numString.Substring(12, 2), out nSec);
DateTime dateFromString = new DateTime(nY, nMM, nD, nH, nM, nSec);
if(dateFromString.Date == yesterday.Date)
Console.WriteLine("dateFromString = {0}\nToday={1}\nEval= {2}", dateFromString, yesterday, answer);