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Toward an API for the real numbers
10-07-2020, 05:40 PM
Post: #7
RE: Toward an API for the real numbers
(10-07-2020 01:35 PM)KeithB Wrote:  but AFAIK, Excel does not use it.

Yes, sure Excel uses doubles. MS early on advertised Excel as the fastest spreadsheet software for IBM PC and hence the battle was for speed rather than "decimal accuracy" of BCD when used in financial calculations. I should have been a bit more careful by stating "some of the early spreadsheet software used BCD".

A quick demo in Excel:
Enter 1.01 in cell A1
Enter =A1+0.001 in cell A2
Copy cell A2 to cells A3-A100
Format column A to 14 decimal places
Cells A47 to A100 show 1.05599999999999 to 1.10899999999999

It's sad that VisiCalc is largely forgotten as the first spreadsheet invention. Everything that came after is an incremental improvement. VisiCalc was implemented by programmers that were familiar with COBOL. For "business computing reasons", COBOL used packet BCD.

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RE: Toward an API for the real numbers - robve - 10-07-2020 05:40 PM

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