Binary search, for strings in an array

[praclarush]

Hey everyone, I’m new at Java and I’m having a bit of trouble. I have an assignment in which I have an Array of objects. The user is to input a name, which then needs to be found in the Array so that the information for that name is displayed. My problem is that i was told to use a binary search and I'm not supposed to use the Arrays class. I know how to do a binary search when the array contains numbers. But I am unsure of how to do it when it contains strings. Can any one give me an example of how I can do this or is it impossible to do with out the Arrays class?

Thanks,
Praclarush

[JosAH]

You should have asked your question in the Java Forum section, not in the Java
Articles section. I'll move your question for you.

kind regards,

Jos

[praclarush]

opps sorry i thought it was in the forums area my bad

thanks,
Praclarush

[Ganon11]

Well, instead of testing for equality with '==', use the .equalsIgnoreCase() method of the String class. Other than that, it works exactly the same.

In fact, you can create a generalized binarySearch method that accepts a Comparable object (Comparable is an interface which many classes support). You can't use .equalsIgnoreCase in this case, but you can still use .equals() (which is required by the Comparable interface).

You will also need to use the .compareTo method to see if the current string is less than or greater than the search String. (In fact, it might be easier just to call .compareTo once and use that value for your tests).

You can check out all of these methods at the Java API here.

EDIT: Whoops, if you use a Comparable object, you can't use .equals(). It's not supported. But .compareTo() does all you need, and this can still work.

[praclarush]

Ok, I managed to get it working, thanks a lot for the help Ganon11

Thanks again,
praclarush