Settle an Argument: String vs. Array?

Definetly 'False' IMO. While .NET string is indeed implemented using array data structure (and that's not the same as Array type) you can only assume that. Without looking at the source code of string know for sure. And even though I know it for sure, I still would answer 'False' because you can't use

char[] charStr = { 'h', 'e', 'l', 'l', 'o', '\0' };
string trueStr = "hello";

the same way.

This question can be answered as 'True' if it was asked as "String is, most probably, implemented internally using array data structure". Because in initial form (A string is the same thing as an array), it can still be considered false even in C.

Well of course they aren't the same, in the same way that a cat is not the same as a dog because they are both mammals and a crab is not a spider even because they are both from phylum arthropoda; though I've had teachers tell my children the latter, thus necessitating a daddy lecture on evolution, biological classification of species, and the importance of never relying on single-sources - and yes, even daddy can be wrong, so here's how you use Google.

But I digress...

That a "string" is not the same as an "array" (and a "String" isn't the same as an "Array" either, and mix-match), so much so that either it was just a bad question (it happens), or it was a devious one; that is to say, see how someone responds to someone being incorrect about something, sloppy logic, "just being an HR person", etc. The base of Human Resources is Industrial/Organizational Psychology (or "work psychology" less formally and especially around Europe), and as a double-major in Psychology I assure you that there are few things more interesting to the common psychology student than observing how people respond to unexpected stimuli.

It might have been a silly bad question, of course, or it was a really simple trick to see how someone deals with someone they view as not technically inclined, to attempt to evaluate conflict resolution, communication, interpersonal/team skills, temperament, self-confidence, etc. Some people get indignant, insulting, condescending, falsely agreeable, overconfident, extremely self-conscious and unconfident...YMMV. No sensible person would throw out an applicant because they missed a trick/wrong question like this, but they absolutely would throw out someone who responded particularly poorly - or recommend someone for their excellent communication skills for handling it gracefully.

One must never assume they know who they are really talking to, and every moment is an invitation to show your KSAO's: Knowledge, Skills, Abilities, and Other Characteristics. Of course the interview has consistently been shown to be one of the least effective methods in existence for hiring - usually worse than blind resume-based picks and reference verification alone - but who listens to psychologists anyway? :)

Technically Speaking...

In C# .NET 4.5 Framework a String is a system class, inheriting from System.Object, which is made up chiefly of two pieces of data - a length of an internal array, and an array of Unicode Characters.

An Array, on the other hand, inherits from System.Object as well, and exposes functionality to handle arrays of many varieties.

While 'string' is an alias for String in C#, in addition to being a relatively fundamental programming concept and data structure, 'array' is just a concept and data structure and only appears in C# as a big-letter Array class and effectively aliased with brackets instead of a simple keyword.

One could thus say a "string" is a type (or involves an implementation) of an array, but:

String != Array

QED

Though the question is baseless without more information, one can argue that from C programming point of view, an array has to boil down to consecutive memory and strings too does the same.

The question is a silly question without qualification. Without specifying the language in the original question, there is no way of knowing the intended answer.

If the question was "is the default implementation of a string an array in C" then the answer would be "yes". If the question was "is a string always an array" then the answer is no, as a string could be implemented in any number of ways, including but not limited to as an array of bytes or a linked list of characters. Even in C#, a string may be null, which is NOT an array.

The problem here is that the recruiter was given a question that they were meant to ask, expecting a binary answer. There was no opportunity to clarify what the question was asking.

In these circumstances my answer would have been:

"A string in C# is not an array, but is most likely implemented using an underlying array of characters. This is dependent on many factors and the implementation may be different depending on the implementation of the compiler. It would be perfectly valid for the compiler author to create a string implementation as a linked list of characters."

In layman's words:

• Most languages implement strings as arrays of bytes.
• It may not be true for every language but I suspect most of them do.

Wikipedia:

A string is generally understood as a data type and is often implemented as an array of bytes (or words) that stores a sequence of elements, typically characters, using some character encoding.

You say:

But even so, (considering C#) a string isn't even a character array. In order to do character manipulation on a string (without using concatenation methods), you have to convert the string to a character array.

But that is not true in other languages, for example, in Java you don't have to convert them to a char array.

Java Doc:

For example:

     String str = "abc";

is equivalent to:

     char data[] = {'a', 'b', 'c'};
     String str = new String(data);

It's clear that in Java a String is a wrapper around a char array.

True and false. Depending on how you word the question.

Bringing a programming language into this begins to mix concepts and actual types. An array for example is both of these, how they're implemented may introduce differences (is array based on vector? or is vector based on array? .. but a "vector" as a concept is a specialization of an array)

So, it really depends on which question you're asking.