[9.9] Display All 14 Significant Digits; [9.10] Group Fraction Digits For Easier Reading - Texas Instruments TI-89 Tip List

Function
Title
Text
DropDown STR,LIST,VAR
Request STR,VAR
(Credit to Frank Westlake)

[9.9] Display all 14 significant digits

The TI89/92+ perform floating point calculations with 14 significant digits of resolution. However, you
cannot set the display mode format to show all these digits. The regression calculations, however, do
display all 14 digits.
You can see all 14 digits for a number in the history area, though - just return it to the command line.
For example, if the display mode is set to Float 12, then entering 'pi' will display
3.14159265359
but if you select it in the history area, it is shown in the command line as
3.1415926535898
Note that, in general, these 2 extra digits are probably not accurate or significant. Any computer or
calculator that performs floating point arithmetic includes one or two 'guard digits'. These digits are
used during calculations to eliminate or reduce round-off errors, especially during long calculation
sequences. That is why the 89/92+ use them during calculations, but do not normally let you display
them.

[9.10] Group fraction digits for easier reading

If you often work with numbers with many digits, it is tedious and tiresome to read the numbers and
copy them without making a mistake. These two routines help somewhat, by converting the number to
a string with spaces between the fractional digits. I show two routines:
grpfrc(x,f)
grpfrcan()
Properties
!
Maximum length of Title string is 50 characters
!
The Title string may be empty; Title ""
!
Maximum length of Text string is 30 characters.
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If a Dialog box contains Text functions, at least one must contain text.
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STR may be empty.
!
The maximum length of STR depends on the length of the widest element
in LIST. If STR has 36 characters, LIST elements must have zero
characters. If STR has 0 characters, LIST elements may have up to 30
characters. Otherwise, the sum of the number of characters of STR and
the widest element of list must be less than or equal to 35.
!
LIST may not have any elements wider than 30 characters.
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LIST may have a single empty string.
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LIST may not have more than 2000 elements.
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STR may have zero characters
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STR can be up to 20 characters, maximum.
Is a function that returns x as a string, with groups of f digits. This routine
is best used in a program, for displaying results.
Shows the latest answer in the history display as a string with grouped fraction
digits. This routine is best used from the command line, to display the last
answer. The number of group fraction digits is fixed, but can be easily changed
9 - 10