# UmAlQuraCalendar.ToFourDigitYear(Int32) Method

## Definition

Converts the specified year to a four-digit year by using the TwoDigitYearMax property to determine the appropriate century.

``````public:
override int ToFourDigitYear(int year);``````
``public override int ToFourDigitYear (int year);``
``override this.ToFourDigitYear : int -> int``
``Public Overrides Function ToFourDigitYear (year As Integer) As Integer``

#### Parameters

year
Int32

A 2-digit year from 0 through 99, or a 4-digit Um Al Qura calendar year from 1318 through 1450.

#### Returns

Int32

If the `year` parameter is a 2-digit year, the return value is the corresponding 4-digit year. If the `year` parameter is a 4-digit year, the return value is the unchanged `year` parameter.

#### Exceptions

`year` is outside the range supported by this calendar.

## Remarks

The ToFourDigitYear method uses the `year` parameter, the TwoDigitYearMax property, and a year to calculate a 4-digit year. The century is determined by finding the sole occurrence of the 2-digit `year` parameter within that 100-year range. For example, if TwoDigitYearMax is set to 1429, the 100-year range is from 1330 through 1429. Therefore, a 2-digit value of 30 is interpreted as 1330, while a 2-digit value of 29 is interpreted as 1429.

If the TwoDigitYearMax property is the special value 99, the ToFourDigitYear method ignores the settings in the regional and language options in Control Panel and returns the `year` parameter unchanged.

ToFourDigitYear supports either a two-digit year or a four-digit year. Passing a two-digit year value (less than 100) causes the method to convert the value to a four-digit value according to the TwoDigitYearMax value representing the appropriate century. If the application supplies a four-digit year value that is within the supported calendar range to ToFourDigitYear, the method returns the actual input value. If the application supplies a four-digit value that is outside the supported calendar range, or if it supplies a negative value, the method throws an exception.