searching

Question

hellow I want to add a search item to my program. I don't know how to start with it. How do i need to do it. When I put an a in a textbox I need to get all the names starting with an a ... can somebody help me with this please? thx and greetings

spgilmore · Answer

Where are the names stored? If they're stored in a database execute a query. This may be intense if you run it for every keypress even if you have an index. To help use a delayed lookup so that they can enter several characters if they know them. If they are stored in memory or in a text file you'll have to search sequentially unless one of two things is true: 1) The items are indexed 2) The items are sorted If the items are indexed use the index to find the items and display them one at a time. If the items are sorted you can do a binary search. This means that you start in the middle of the data and read an item. You determine if the item you're looking for comes before or after the middle item. When you make that determination you have cut your search in half. (The two halves are called partitions). Do the same thing on that half of the data and you have cut your search in half again. Do this repeatedly until you come to an item that matches your criteria. If there are no items the partition size will be 1 and it will not match. If a match is found search up to find the first item then move through all the items one at a time (sequential search) since they will all be contiguous. Stop when you find an item that doesn't match.