i am trying to write a program to find the day of any date.

WEEKDAY Day of week. DAYNUM = WEEKDAY(T) returns the day of the week number for each element of T. T is a numeric array containing serial date numbers. T can also be a cell vector, character matrix, or string array containing date strings in one of the following formats (see DATESTR for more details about date formats): * mm/dd/yyyy * dd-mmm-yyyy * yyyy-mm-dd For dates in another format, use WEEKDAY(DATENUM(DATE,FORMAT)). WEEKDAY assigns the days of the week the following values in DAYNUM: Sun: 1, Mon: 2, Tue: 3, Wed: 4, Thu: 5, Fri: 6, Sat: 7 [DAYNUM,DAYNAME] = WEEKDAY(T) also returns the day name for each element of T. DAYNAME contains short day names in English. [DAYNUM,DAYNAME] = WEEKDAY(T, DAYFORM) controls the format of the names in DAYNAME. When DAYFORM is 'short' (the default), WEEKDAY returns short day names. When DAYFORM is 'long', WEEKDAY returns full day names. [DAYNUM,DAYNAME] = WEEKDAY(T, LANGUAGE) controls the language of the names in DAYNAME. When LANGUAGE is 'en_US' (the default), WEEKDAY returns English day names. When LANGUAGE is 'local', WEEKDAY returns names in the local language. DAYFORM and LANGUAGE are optional and can be combined in any order following T. Examples: [num,name] = weekday(728647) [num,name] = weekday('19-Dec-1994') [num,name] = weekday('19-Dec-1994','long','local') [num,name] = weekday(datenum('12/19/1994','mm/dd/yyyy')) See also EOMDAY, DATENUM, DATEVEC. Documentation for weekday doc weekday