This is the type of question an interviewer will ask if he starts to doubt your ability to perform certain duties revolving around algorithm-based development. Since software development, at some level, relies on algorithms and data structures, this will be an important question that you must understand and answer properly. If we look at how the binary search structure is broken down, it contains a binary search or half-interval search, a divide and conquer algorithm that seeks a position of an item in a sorted array. When a hiring manager asks about comparing inputs and output to the middle element of an array, they are asking if a search returns the position of an element. It's important to know and understand this concept. Another question that may be asked is whether or not an input is less than or greater than an element. If you have a sound understanding of these concepts, ask the interviewer what level of detail they would like to answer their question. Some interviewers only want to hear a high-level answer, and others want a detailed explanation.