It will return the day by 1(Monday)...7(Sunday) when you export a valid date to this function module. The return values can be interpreted as follows :
Monday, if System will return value = 1
Tuesday, if System will return value = 2
Wednesday, if System will return value = 3
Thursday, if System will return value = 4
Friday, if System will return value = 5
Saturday, if System will return value = 6
Sunday, if System will return value = 7
Check the example below to see the FM call :
CALL FUNCTION ’DATE_COMPUTE_DAY’
EXPORTING
date = date
IMPORTING
DAY = day. "Returns Value out of the range 1(Monday)...7(Sunday)