usedI

usedI is a mnemonic identifier that appears in programming literature and example code to denote an index i that has been marked as "used" within a procedure. It is not a formal language feature or standardized term; its exact meaning depends on context and the coding conventions in use.

The name combines the verb used with the common single-letter index I. In practice, usedI often stands for a boolean flag or a state value associated with the i-th element, indicating that this element has already been processed, selected, or allocated during an algorithm’s execution.

In pseudocode and examples, usedI is typically paired with an array or structure that tracks usage across indices. For instance, a permutation or combination generator may maintain a used[] array, and the narrative shorthand might refer to the current i-th flag as usedI. Writers sometimes use usedI as a shorthand for isUsed[i] or to label a temporary state variable within a loop or recursive call.

Best practices emphasize clarity: prefer descriptive names such as isUsedIndex, usedIndexFlag, or used[i], especially in larger codebases, so readers do not misinterpret the term. When usedI appears without context, its meaning can be ambiguous and lead to errors or confusion across languages with different scoping and naming rules.

See also: boolean flag, variable naming, index variable, backtracking, pseudocode.