Is it Possible to Check Speacial Character in Binary search in java? [closed]

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my String Buffer has "_ @ ." .I have Binary Search method that return false for char '.'. i can not find how to check speacial character in Binary Search.Please help to find out this issue .

Answer 1

Correct me if I am wrong, but binary search is used on sorted arrays.

You are trying to perform binary search on array of chars _ @ ..
In terms of ASCII codes, that looks like this: [32][95][32][64][32][46].

So, when you call your function:
Low: 0 - Middle: 2 - High: 5
Seach: 46 - Actual: 32
Low: 3
Low: 3 - Middle: 4 - High: 5
Seach: 46 - Actual: 32
Low: 5
Low: 5 - Middle: 5 - High: 5
Found!!!
true

However, when you take out the empty spaces and run it over "_@."

Low: 0 - Middle: 1 - High: 2
Seach: 46 - Actual: 64
High: 0
Low: 0 - Middle: 0 - High: 0
Seach: 46 - Actual: 95
High: -1
Not found!!!
false

To summarize:

If you are absolutely sure you'll be running your search over a sorted array, then this is OK.

However, like in your case, if you can't guarantee that you'll have sorted array, then don't use binary search.

Answer 2

you called wrong function. change like this..

public static void main(String[] args) {
    StringBuffer b = new StringBuffer();
    b.append(" _ @ .");
    boolean isValid = false;
    isValid = isValueThere(b, '.');
    System.out.print(isValid);
}

and isValueThere(b, '.'); return true.