Don't-care (logic)

In digital logic, a don't-care term is an input to a function that the designer does not care about, usually because that input would never happen, or because differences in that input would not result in any changes to the output. By using these don't-care inputs, designers can potentially minimize their function much more so than if the don't-care inputs were taken to have an output of all 0 or all 1. Don't-care terms are important to consider in minimizing using Karnaugh maps and the Quine–McCluskey algorithm.