# How do we differentiate between a computer and a calculator?

In this SO Question there is a comment by `starblue` that

A computer without loops is a calculator

Is this true?
Is that the only difference?
Is there a set of criteria to differentiate or has the line become very blurred?

• Don't take short, single-sentence definitions like this for absolute truths. They are ofen an example of ha-ha-only-serious and not meant to be absolutely, unquestionably true in all cases. Dec 20 '12 at 12:54
• I only have to say this. Haskell do not have any loop constructs. So if the above is true, Haskell is only good for creating calculators. Dec 20 '12 at 13:28
• @ManojR: Recursion is a form of looping construct. Dec 20 '12 at 14:33
• Calculators compute things, thus they're computers in my view. Have a look here for a little history of the word computer, it meant non-electronic for longer than it has meant electronic. en.wikipedia.org/wiki/Human_computer Dec 20 '12 at 15:56
• All calculators are computers. Not all computers are calculators. Dec 20 '12 at 16:57

## 3 Answers

a computer is generally turing complete

whereas the calculator is either a Pushdown Automaton (when it has brackets and priority of operations) or a Finite State Automat when it doesn't (it excecutes the next operation on the last result)

• Of course, strictly speaking, any real world computer is a finite state automaton. Dec 20 '12 at 13:14
• In layman's terms, you could say that a computer is a general purpose device that can do anything. A calculator can only perform a specific set of tasks. Dec 20 '12 at 13:45
• No, 90-99% of programming calculators were turing complete, too. At least what was sold by this name. Dec 20 '12 at 14:55
• And any computer or calculator is a finite state automate Dec 23 '12 at 10:04
1. A universal positive unconditional sentence cannot be true. (This one, for example, is universal, but negative). Here Joachim Sauer is correct.

2. "A computer without loops is a calculator" is a definition. It cannot be true or false at all. You can accept it or not.

3. But any definition can be widely or universally accepted or not to be. Or maybe it was sometimes accepted. Here you should choose yourself, what do you want.

4. As for history, in the middle of the XX century in fantastic literature all computers were called calculators. Later, in 70/80-ties, programmable calculators had hundreds of command places, arrays, cycles, conditional branches, gotos and everything. As I remember, much more programs were made for them than for "large" computers.

5. Now programmable calculators are a minor business, but they do exist and there are new models of them. Look here.

So, the answers are: no; no(difference is in size mostly); yes, it is blurred. Of course, as far as you take wiki as widely accepted opinion

• "A universal positive sentence cannot be true" 1 always equals 1 Dec 20 '12 at 14:54
• Sorry, I can't find the correct English word. We are talking about real life, not mathematics. Any mathematician sentence is conditional, even if it doesn't seem so. Conditional sentences yes, can be universal positive and true. Answer is edited. Dec 20 '12 at 14:59

It's not true if you're talking about a standard calculator. I would consider conditionals to be very important here as well.