An
off-by-one error (
OBOE), also commonly known as an
OBOB (
off-by-one bug), is a
logic error involving the discrete equivalent of a
boundary condition. It often occurs in
computer programming when an
iterative loop iterates one time too many or too few. This problem could arise when a programmer makes mistakes such as using "is less than or equal to" where "is less than" should have been used in a comparison or fails to take into account that a sequence starts at zero rather than one (as with array indices in many languages). This can also occur in a
mathematical context.