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Have you wrote a calculator?
Yes 29%  29%  [ 14 ]
Yes 29%  29%  [ 14 ]
no 21%  21%  [ 10 ]
no 21%  21%  [ 10 ]
Total votes : 48

mic
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30 Jun 2004, 10:12 am

I tried to write one in C++ but failed. In whatever language you know have you wrote a calculator.



Bruno
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10 Jul 2004, 9:38 am

I did some math helping tools in flash, quite useful.



MoonPatrol
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10 Jul 2004, 6:53 pm

What sort of calculator? One of those ones with the buttons? I wrote a simple one of those once in Smalltalk.



synx13
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11 Jul 2004, 5:28 pm

Writing a calculator is a pretty standard exercise for those studying language parsers. I've put together one before.



MoonPatrol
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11 Jul 2004, 7:16 pm

I'm unclear about what we are talking about here. Are we talking about an expression evaluator that you give a string like say "3 * 2 + 5" and it comes back with a result, or are we talking about a "desktop" calculator that has buttons you can click?



Tom_FL_MA
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11 Jul 2004, 7:25 pm

I am a perplexed myself, MoonPatrol.



mic
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12 Jul 2004, 2:27 pm

Quote:
Are we talking about an expression evaluator that you give a string like say "3 * 2 + 5" and it comes back with a result

That type of calculator is what I mean.



Tom_FL_MA
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12 Jul 2004, 4:01 pm

I get it, interesting term to give it. :)



MoonPatrol
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13 Jul 2004, 1:58 am

mic wrote:
Quote:
Are we talking about an expression evaluator that you give a string like say "3 * 2 + 5" and it comes back with a result

That type of calculator is what I mean.

Are you interested in solving this problem from a pragmatic point of view (that is, "how do you write an arithmetic expression evaluator with the least amount of effort?"), or from a theoretical point of view ("how do these things work?").

From a pragmatic point of view in C++, you would find some library that someone has already written and just use that. Some other languages have a built-in evaluator that you could use.

From a theoretical point of view, we are getting into parsing, and things start to get complicated ...



NooneInParticular
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13 Jul 2004, 12:04 pm

Writing an RPN (reverse polish notation) calculator is pretty easy in most langugages... parsing is handled by employing a simple LIFO-type data structure like a stack.

There is even hardware that uses LPN, namely HP calculators.




MoonPatrol wrote:
mic wrote:
Quote:
Are we talking about an expression evaluator that you give a string like say "3 * 2 + 5" and it comes back with a result

That type of calculator is what I mean.

Are you interested in solving this problem from a pragmatic point of view (that is, "how do you write an arithmetic expression evaluator with the least amount of effort?"), or from a theoretical point of view ("how do these things work?").

From a pragmatic point of view in C++, you would find some library that someone has already written and just use that. Some other languages have a built-in evaluator that you could use.

From a theoretical point of view, we are getting into parsing, and things start to get complicated ...



MoonPatrol
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15 Jul 2004, 4:18 pm

NooneInParticular wrote:
Writing an RPN (reverse polish notation) calculator is pretty easy in most langugages... parsing is handled by employing a simple LIFO-type data structure like a stack.

There is even hardware that uses LPN, namely HP calculators.

Yes, and a classic way of evaluating normal ("infix") arithmetic expression is to convert them to RPN (or "postfix") first. There's an algorithm out there to do this.



macvincent
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07 Aug 2004, 11:20 pm

I have written a calculator in PHP where you type in an expression and it solves it for you.

Once I tried writing a "button" calculator using html and javascript but it didn't work too well.



baseballfan
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26 Oct 2004, 11:17 pm

I created a calculator back in my high school CS1 days. By the way, you might want to change the topic to read: Have you "written" a calculator.



MishLuvsHer2Boys
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27 Oct 2004, 6:51 am

I was never into programming but I had a cousin that did that. It was kinda neat.



Feste-Fenris
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27 Oct 2004, 8:35 pm

I once used BASIC to make a celsius farenheit converter...

So Farenheit 911 equals Celsius 450...

Bung!



Tom_FL_MA
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28 Oct 2004, 5:07 pm

Feste-Fenris wrote:
So Farenheit 911 equals Celsius 450...


911°F = 488°C

To convert Celsius to Fahrenheit: °F = 1.8 x °C + 32 | {9/5 = 1.80}

To convert Fahrenheit to Celsius: °C = °F - 32 x .555 | {5/9 = .555}


Here's how it's broken down: 1.8 x 488°C + 32 = 910.4°F, rounded to 911°F &
                                               911°F - 32 x .555 = 487.8°C, rounded to 488°C