What algorithm is used to search for structured data that must be ordered?

The algorithm used to search for structured data that must be ordered is binary search. This search algorithm operates on sorted data, taking advantage of the order to efficiently locate a target value. It works by repeatedly dividing the search interval in half. The process begins by comparing the target value to the middle element of the data set. If the target value matches the middle element, the search is complete. If the target value is less than the middle element, the search continues on the left half of the data; if greater, it continues on the right half. This halving process significantly reduces the number of comparisons needed to find the target, making binary search much faster than a linear approach, particularly for large datasets.

In contrast, linear search does not require the data to be ordered and instead checks each element sequentially until the target is found, leading to inefficiencies with larger datasets. Bubble sort and selection sort are sorting algorithms, not searching algorithms, and their function is to organize unsorted data rather than to find a specific value within ordered data. Hence, binary search is the most effective choice when dealing with structured data that is already ordered.