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The C++ Pocket Calculator Library


This project consists out of a set of C++ classes for Linux and Windows with wich you can implement virtual pocket calculators in a relative easy way. This is true especially for my own old calculators, therefore the name: Almetare means "Alle meine Taschenrechner" - the German phrase for "all my pocket calculators" (Almypoca wouldn't sound so bad as well). It is my goal to rebuild all my calculators for use on the PC in the future. (After 20 years meanwhile the hope to reach this objective seems to be not so big, I fear.)

Three calculators are finished till now. They imitate the originals in nearly all details. Even the key click or automatic power off if there is no input for some minutes  (you may disable these features in a configuration dialog of course).

But, the algorithms of the calculators are not copied; in this point I rely completely on the compiler's mathematical library (I don't call the calculators "emulators" therefore). That means especially that the virtual calculators compute with better accuracy (about 15 digits) than the originals (8 to 12 digits). But the user should not notice that.

Unfortunately the Linux version is not in a good state: The graphical user interface is implemented with the Qt library version 2. In the meantime version 5.9 is available, not compatible with the old version. Since Qt 4 I failed compiling the project under Linux because I have not had the time to make the necessary adjustments. It is much easier under Windows to install the old Qt version and to compile the project with it. There should Linux take a leaf out of Window's book ... However, under Wine the Windows versions can be used without problems.

The sources are published under the GNU GPL. You can get them and the binaries from below.

Texas Instruments TI-30

TI-30 The TI-30 was the calculator in German schools in the end of the seventies of the last century. You could not read its red LED display quite well (must look in the exact angle through the little magnifier lenses in front of the tiny digits) and it needed much battery power. One could really watch it doing its calculations: Thinking on "sophisticated" tasks, as sine or cosine, could take about a second, and the calculator enjoyed its impatient owner with interesting blinking effects in this time (to imitate this spectacle has cost quite a lot effort). Getting older the keys became bouncing; besides that the calculator managed its tasks because of its clear arrangement very good. The calculator cost about 30,- DM if ordered collective, as far as I can remember, and was worth its money.

Casio fx-3600P

Casio fx-3600P

Although not very much younger (bought in 1982 for 89,- DM) the fx-3600P belonged to a complete other generation of calculators compared to the TI-30: 10-digit LC display (plus two digits for the exponent), seven independent (non volatile) memories, a lot of more functions (statistical, regressional, integral calculations), keyboard a little spongy but quite usable (and first of all absolutely free of bouncing) outpaced the TI. And the most important thing: The calculator has been programmable! Though the program memory could hold only 38 "program steps" you could do more with it than you might imagine. To me this has been the first step into the world of programming. The only thing I had missed was the conversion of numbers in different number systems. Especially to mention is its unbelievable low power consumption. I have really the first battery in it!
The Almetare calculator can store an arbitrary number of program steps and save the programs to a file. Additionally there is a simple program editor and an editor for entering values in statistical calculations.

Casio fx-85v

Casio fx-3600P

This calculator was bought in 1992 and is in my possession as a loan. Its functionality and operating is like the fx-3600P, but it is not programmable, there are no integral calculations and the keyboard is a rubber pad. It is solar powered, to save the constant memories and for operation in faint light there is also a battery.
Besides the TI-30 this is the second Almetare calculator.


Almetare_1.20_setup.exe 2504 kB All three calculators (incl. manuals and Qt DLL), combined in a single Windows installer. 1.20 Windows1) 2982 kB All three calculators (incl. manuals and Qt DLL), combined in a Zip file instead in an installer. 1.20 Windows1)
Almetare_src_1.20.7z 3838 kB Source files and documentation of all calculators, makefiles, workspaces for KDevelop 2 (SuSE 8.1), KDevelop 3 (Knoppix 3.7) and Visual Studio 6, API documentation, class diagrams etc., but no binaries. 1.20 Windows1) und Linux2)
QtWin230-NonCommercial.exe 10556 kB For compiling the sources Qt2 for Visual Studio 6 is necessary. Because you cannot find this old version easily nowadays use the adjacent link. 2.3 Windows

1) tested with Windows XP to Windows 11
2) tested with SuSE Linux 8.1, Knoppix 3.8 und Knoppix 4.0

Change Log

7 January 2024, V.1.20:
  • Exponential operations x1/y with negative y resulted in an error, even in case of an odd y.
23 July 2022, V.1.19:
  • When entering numbers in the interval ]-1,1[ the Casio fx-3600P crashed if the maximal number of digits has been exceeded. The other two calculators are unchanged.
2 July 2022, V.1.18:
  • Casio fx-3600P: Bei der Eingabe von Zahlen mit Dezimalpunkt durften fälschlich nur zehn statt elf Ziffern eingegeben werden.
  • Casio fx-85v und TI-30:
    • The last change in the Casio fx-3600P caused unfortunately that after entering a number with eight digits a minus sign was not accepted any longer.
    • When entering numbers with decimal point only seven digits could be keyed in instead of eight.
16 June 2022, V.1.17:
  • The Casio fx-3600P crashed when pressing the "+/-" key and the display contained already the maximal number of digits to the left of the decimal point. The other two calculators are unchanged with the exception of the version number.
23 June 2019, V.1.16:
  • Finally the ESC key works even with the TI-30 as promised with V.1.14 already. The other two calculators are unchanged with the exception of the version number.
9 May 2018, V.1.15:
  • Casio fx-3600P: Due to an user request you can now call from a program the other program as a subroutine (but only when using the program editor).
  • Casio fx-3600P: When trying to integrate a function containing an ENT or a HLT statement the calculator switches into the error state now like the original.
  • All calculators are compiled with Service Pack 6 of Visual Studio 6.
18 February 2017, V.1.14:
  • Due to a user request the shortcut keys are modified a little: The Casio calculators' key AC can be triggered now with "a" instead of "A", the key C with "c" instead of "C". You do not need to press the shift key anymore therefore. In all calculators the ESC key clears the display as well.
  • The rounding in the display has been too rigorously sometimes.
27 June 2014: V.1.13:
  • The Casio calculators have delivered 3 instead of 5 when doing a (not meaningful) calculation of kind "2 % + 3 =".
  • After percentage calculations with automatic add-on like "200 * 10 % +" the Casio calculators switched into the constant mode if the next key has been "+" again.
  • The TI-30 switched into scientific notation in case of absolute values less than 0.01 already instead of 1e-7.
  • Doing calculations like "200 * 10 % + 3 =" the TI-30 delivered 3 instead of 23.
19 January 2014, V.1.12:
  • When doing regression analysis the x-value has been calculated wrong if the y-value contains only a single digit.
  • Under Windows 7 the help file could not be opened with the help dialog or with function key F1 if the installation path contained spaces.
  • There is an installation wizard available now.
9 October 2005: V.1.11:
  • Casio calculators: Rounding error in conversion from decimal to sexagesimal numbers fixed: E.g. the conversion of 2.0333333 results in 2°1°60 instead of 2°2°0.
  • Besides Ctrl-C and Ctrl-V you can use Ctrl-Insert and Shift-Insert for copy and paste.
  • As under Linux also under Windows the configuration file is created in the user's home directory, not in the program directory.
23 January 2005, V.1.10:
  • Data editor is available (Casio fx-3600P and Casio fx-85v).
  • Pasting data with Ctrl-V from the clipboard into the display works again under Windows.
  • Minor bugfixes.
22 February 2004, V.1.00:
  • DCall of a function (sine, cosine etc.) immediately after starting the calculator does not result in a crash any longer.
  • There is the option "always on top" in the configuration dialog now.
  • Desktop- and dialog icons added.
15 August 2003, V.0.99:
  • Entering of e.g. "3 ab/c sin" does not result in a crash any longer (Casio).
  • It is possible to paste numbers into the calculator with CTRL-v now, and even whole sequences of key clicks using the shortcut symbols.
  • Integral calculus improved (Casio fx-3600P).
5 August 2003, V.0.98:
  • Incomplete operations in combination with function calculations reachable by the INV key led to the same problems as described below. Example: "5 * INV 10x =" delivered 105*105 = 1e10 (Casio Calculators) or 1*105 = 1e5 (TI-30) instead of 500000.
  • Casio calculators: Entering of e.g. "5 * INV M-" resulted in 0.25 instead of 25.
  • TI-30: Shifting of the exponent with "EE" and "INV EE" works again.
2 August 2003: V.0.97:
  • Incomplete operations in combination with function calculations delivered not the same result as the original calculator. Example: Entering "5*ln=" resulted in ln(5)*ln(5)=2.590... (Casio fx-3600P and Casio fx-85v) or 1*ln(5)=1.609... (TI-30) instead of 5*ln(5)=8.047...
  • An incomplete operation of the kind "5*=" entered directly after switching on the calculator delivered correctly 25 (Casio fx-3600P and Casio fx-85v) or 5 (TI-30). But, entering "5*=" a second time gave the errornous result of 0.
18 May 2003, V.0.96:
  • Crash when starting as console application fixed.
  • Starting the default help browser under Windows XP will work now.
  • Error in sexagesimal calculations fixed (Casio fx-85v).
  • The operator x1/y may be used as constant operator too now (Casio fx-85v).
  • The display is improved (Casio fx-85v).
  • Storing of configuration is done now not only if closing the calculator with the "OFF"-Button but if closing with the window closer "x" as well (TI-30).
  • Immediately after the start of the calculator e.g. the calculation "6*=" resulted to 36 (TI-30: 6) instead to 0. This is fixed.


    Mike Sebastian's site contains much technical information on calculators of various manufacturers, testing functions to figure out the chip and more.
    Very detailed site especially about Texas Instruments and its pocket calculators by Jörg Wörner.
    Special site about programmable calculators of various manufacturers by Viktor T. Toth (thanks for his help finding some bugs in versions 0.96 and 0.97!).
    Calculator simulators of the British trade name "Anita".