Students Calculator for JAVA phones

by :VoxeL: aka absorbb

I'd like to present to you JAVA calculator for students with input of the string from keyboard.
The problem with paucity of buttons was sold by separation of functions onto 4 levels:
1st – digits’s and “.”
2nd – sin, cos, tan, *, /, +, (), square, square root,
3d – asin, acos, atan, ln, log, exp(x), (-), 10x, π, xy, n-th root,
4th – sh, CH, th, ash, ach, ath, ANS (inserts the answer into the line), abs, the factorial, X.Y (variables given by user).
Levels are switched by #.
It is checked, that the speed of entry on it is mostly the same as in usual calculators. As a maximum it will be necessary fpr an operator to press button 4 times to press button, and since the majority of pressures is fallen to the numbers, then on the average it will come out near 1 pressure :)
Calculator provides approximately 16 decimal digits accuracy. For calculations with the numbers with floating point it uses class Real.java from Roar Lauritzsen.
Calculator is written under MIDP1.0 and CLDC1.0
Additionally:

1. Calculator has history of entries from 9 lines.
2. There is a possibility to assign 2 user variables and to use them in the calculations.
3. Tuning format of angular arguments (degrees/radians) through Settings menu.
4. The possibility to calculate in HEX, OCT, BIN systems! Some additional functions is available in these modes, such as div, or, and, mod, xor, not, >>, << (since 1.5.0)
5. Tuning format of output answer (FIX, SCI, ENG) and quantity of digits.
6. There is possibility of reassignment keys DIAL, FIRE, NODIAL (only for some telephones) through Settings menu.
7. There is possibility to copy answer (ANS to text) into the buffer on telephones, supporting copying text.
8. There is possibility to convert answer to simple fraction (ANS to a/b). Algorithm is approximate. If it fail to find accurate fraction, the symbol "E" appears before result.
9. The history of entries and all settings saves on exit.
10. Possibility of entering basic physics constants from Constants menu.

Joystick up/down – navigation on the history of entries. “Down” on the first line creates a new one and deletes upper line. “=” don’t create a new entry in history. Pressing on joystick turns the keyboard into “insert” mode.

Calculator was tested on:
Motorola E398, V620, C380, C650
SonyEricsson K700, T630, T610
Siemens C65 CX65 (Siemens version) ,  SX1
Nokia 6610i, N-Gage
Samsung E800
Theoretically it must work on all telephones supporting JAVA.

Thanks:
JenFA for the source of File Manager, which greatly helped me, for the valuable advice and the moral support.
Busheva Maria aka RNqAM for the inspiration and for the moral support.
Strizhenko Pavel aka Proton for the testing and the project promotion.