A mistake in which a loop count or an array range is off by exactly one. It arises from whether the final value is included, whether indices start at 0 or 1, and confusing the number of intervals with the number of points (the fence-post problem). Tracing with the boundary values makes it easier to find.
Japanese name: オフバイワンエラー
Off-by-one error appears in 2 practice questions across 1 topic, including Programming Basics (Pseudocode Tracing).
Carrying over the pattern for languages whose indices start at 0 (from 0 to length − 1) to arrays that start at 1 causes this kind of off-by-one error.
The following program was meant to compute the sum of all e…As with fence posts, confusing the number of intervals with the number of points causes an off-by-one error.
The following for loop increases its control variable by 5.…As an Amazon Associate I earn from qualifying purchases.
Array Variable Argument Bitwise operation Control structure Integer division Modulo operation Object-oriented programming Pseudocode Return value