what is Binary Search-half interval search in data structure

Binary search or Half interval search

In computer science, a binary search or half-interval search algorithm finds the position of a specified input value (the search "key") within an array sorted by key value

For binary search, the array should be arranged in ascending or descending order.

In each step, the algorithm compares the search key value with the key value of the middle element of the array.

If the keys match, then a matching element has been found and its index, or position, is returned

Otherwise, if the search key is less than the middle element's key, then the algorithm repeats its action on the sub-array to the left of the middle element or, if the search key is greater, on the sub-array to the right.

If the remaining array to be searched is empty, then the key cannot be found in the array and a special "not found" indication is returned.

Algorithm OF Binary Search-half Interval Search

1. [Initialize segment variables.]

  Set BEG=LB, END=UB and MID=INT((BEG+END)/2).

2. Repeat Steps 3 and 4 while BEG ≤ END and DATA[MID]≠ITEM.

3.   If ITEM< DATA[MID]. Then

  Set END=MID-1.

  Else Set BEG=MID+1.

  [End of If Structure.]

4.   Set MID=INT((BEG +END)/2).

[End of Step 2 loop.]

5. If DATA[MID]= ITEM then Set LOC= MID

Else:

  Set LOC = NULL

[End of IF structure.]

6. return LOC and Exit

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