Which error type does the "off-by-one" error belong to?

The "off-by-one" error is classified as a run-time error. This type of error occurs when a program executes and produces incorrect results due to a logical mistake in the code. Specifically, an off-by-one error usually arises from miscalculating an index in loops or array accesses, where the program incorrectly starts or ends one iteration too early or too late.

For example, in scenarios where you need to iterate through an array, using an index that goes one position past the array's boundaries can lead to incorrect data being accessed, or potentially cause the program to crash. This error is not detected at compile time, which is why it is not a compile-time error or a syntax error. Instead, it manifests when the program is running, thus categorizing it as a run-time error. Understanding this distinction is crucial for debugging and designing correct algorithms in programming.