DelphiBasics TwoDigitYearCenturyWindow Variable Sets the century threshold for 2 digit year string conversions SysUtils unit

var TwoDigitYearCenturyWindow : Word;

Description The TwoDigitYearCenturyWindow variable is used when converting 2 digit year date strings to TDateTime values.   The TwoDigitYearCenturyWindow value is subtracted from the current date to set the conversion threshold.   For example :   TwoDigitYearCenturyWindow  : 50 (default) Current year last  : 2002 Threshold is then set  : 1952 100 year window becomes  : 1952 - 2051   When converting a 2 digit string year, such as 75, the 2 digits are compared to the threshold last two digits. If greater, then the date is in the lower century, for example 1975. If lower than the threshold, the date is in the higher century. For example, 44 would give 2044. Notes If the TwoDigitYearCenturyWindow value is zero, then the value is always set in the current century, regardless of the 2 digits value. Related commands StrToDate Converts a date string into a TDateTime value StrToDateTime Converts a date+time string into a TDateTime value  Download this web site as a Windows program.

Example code : Move the threshold to see how a conversion is affected var   myDate : TDateTime;   formattedDate : string; begin   // Set up a date from a 2 digit year using the default threshold   myDate := StrToDate('09/05/30');   ShowMessage('09/05/30 using  default threshold = '+DateToStr(myDate));   // Now change the default threshold to 80 :   // 2002 (at time of writing) - 80 gives 1922   // 30 is above 22, so 1900 century is chosen   TwoDigitYearCenturyWindow := 80;   myDate := StrToDate('09/05/30');   ShowMessage('09/05/30 using override threshold = '+DateToStr(myDate)); end; Show full unit code   09/05/30 using default threshold = 09/05/2030   09/05/30 using override threshold = 09/05/1930

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