I started thinking about working on Calculator II when I found out that the calculator Desk Accessory supplied with my Macintosh didn't give multiplication and division the usual precedence over addition and subtraction. Inaccuracy in representing certain decimal numbers also irritated me. I had found one version of a scientific calculator in the library of a bulletin board somewhere, but it had so many extra functions that it took forever to draw its keypad, and still had problems representing decimal numbers. One thing led to another, and soon I finished Calculator II, a modest scientific calculator.
Version 1.1 includes the following features :
Calculator II has 13 digits of displayable accuracy, with an internal accuracy of 18 digits.
Operational precedence. Operators in greatest to least order are :
unary operators (square root, square, trig functions, etc.), parenthetical notation, exponentiation, multiplication and division, and finally addition and subtraction.
Trigonometric and other scientific functions, including memory. Arguments to trig functions can be expressed as degrees, radians, or gradient.
Deletion of individual digits - if you mess up the last digits in a long string, you don't have to clear the whole thing and start over.
Decimal accuracy. On the original Macintosh calculator, many decimal fractions are not represented with complete accuracy. For example, (0.12 * 10 - 1) * 10 - 2 will result in -6.50521E-19 on the old calculator. Calculator II will give the correct answer of 0. Another example is 99 + 0.0000000001 - 99. On the old calculator, multiplying the answer by 10E+10 will result in 1.0000000134 instead of the correct answer of 1. Calculator II also avoids loss of accuracy when adding small numbers to much larger ones (1e23 + 1e8 - 1e23 = 99999744 on old).
The cutting and pasting of up to 256 characters is supported, taking advantage of the full 18 digits of internal accuracy. Pasting of scientific notation numbers from Calculator II to the old calculator doesn't always work accurately, since the old supports fewer significant digits in scientific notation. You may also paste equations into Calculator II, as in the old, and equations may contain any keystroke that works on Calculator II. In addition, Calculator II silently processes white space, instead of beeping in an annoying fashion. In pasted text, e doubles as Tab for scientific notation; the exact meaning of e depends on context. Some examples include: 13e equals e to the 13th power, 13e+3 equals 13000, but 13e +3 equals e to the 13th power plus 3 ( note space after e ).
Calculator II's key and display layout is saved as a picture, so that window updating after jumps between it an a word processing application, for example, don't slow you down.
Most of Calculator II's functions are self explanatory, but are otherwise explained here :
Repeatedly pressing the '=' button will repeat the last operation.
Exponential or scientific notation is obtained by using the tab key or
clicking the button labeled 'exp'. Typing 'e' will give you e to the x power, not scientific notation. Pasted text operates differently; see above.
' l' - natural log.
'n' - factorial.
'd' - 'drg' button; toggles between degrees, radians, or gradient notation.
'c','s','t' - cosine, sine, and tangent functions. Use uppercase for inverse functions.
Using the delete key or clicking in the left arrow button deletes trailing digits that have been mistyped.
'y' - binary operator for exponentiation.
'r' - square root.
'x' - square.
'[' - recall from memory.
']' - transfer to memory.
Typing a single quote will add to memory.
';' - same as clicking in button labeled '+/-'. Toggles the sign of the displayed number or its exponent, if in scientific notation.
