Array.binarySearch returning wrong data

Question

I am trying to validate password and username using array and the array.BinarySearch function. The first two user names in the array: bradley and john are returning the correct

Answer 1

Your names array is not sorted:

String[] names = {"bradley","john","jim","clarke"};

which is a requirement of binarySearch() (and binary searching algorithm in general):

The range must be sorted into ascending order

Sort it first and it'll work like a charm:

String[] names = {"bradley","clarke","jim","john"};

Answer 2

A binary search requires the array to be sorted before hand. You can either list the names in order, or perform the sorting yourself. You can use Arrays.sort(names) to sort the array of names.