Outputing a REAL - not cm3 specific

[dukester]

Although the issue that I bring here has to do with Oberon-2 code, it could very easily be cm3 code. There seems to be a few mathematicians here so I thought I'd take the liberty and ask for directions here.

I wrote a simple temperature conversion utility - menu driven, C to F or F to C.
It works fine, but in Oberon-2, REALs are output in scientific notation only.

Temperature Conversion Utility
------------------------------
1 - Fahrenheit TO Celsius
2 - Celsius TO Fahrenheit
  - Enter your Choice
1
Enter a number/temperature TO convert: 32

Your input was 3.200000E+01 Fahrenheit!
That's 0.000000E+00 In Celsius!

Would any of you know of a way to convert the above output to a one decimal place REAL?
My goal is to port the code cm3 as a learning exercise, but I want to get my head around of how to tweak the above output to something a non math guru would understand. TIA!

[RodneyBates]

Have a look at the Fmt interface in m3-libs/libm3/src/fmtlex/Fmt.i3. Procedure Real formats a REAL into characters in several alternative ways,  I would guess Style.Fix, with prec as the desired number of fractional digits, would probably be what you would want.

…

On 3/30/23 23:20, Duke Normandin wrote: Although the issue that I bring here has to do with Oberon-2 code, it could very easily be cm3 code. There seems to be a few mathematicians here so I thought I'd take the liberty and ask for directions here. I wrote a simple temperature conversion utility - menu driven, C to F or F to C. It works fine, but in Oberon-2, REALs are output in scientific notation only. |Temperature Conversion Utility ------------------------------ 1 - Fahrenheit TO Celsius 2 - Celsius TO Fahrenheit - Enter your Choice 1 Enter a number/temperature TO convert: 32 Your input was 3.200000E+01 Fahrenheit! That's 0.000000E+00 In Celsius! | Would any of you know of a way to convert the above output to a one decimal place REAL? My goal is to port the code cm3 as a learning exercise, but I want to get my head around of how to tweak the above output to something a non math guru would understand. TIA! — Reply to this email directly, view it on GitHub <#1162>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABSVZNHVV3SFXH3NSNKOY7DW6ZLPFANCNFSM6AAAAAAWOEHNVY>. You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[dukester]

Thx Rodney! I'll sure give your Reference a good study. God gave me a lot of talents, but a mathematical mind isn't one of them. I could never "see" the point of calculus etc - until I decided to build my own bamboo flyrod. Everett Garrison, a structural engineer, wrote a book on building bamboo flyrods. He got into the modulus of elasticity of bamboo, taper derivations - the whole nine yards. It wasn't until he explained about getting taper dimensions by calculating - long-hand - the area under the curve created by a flexed flyrod, that I understood what calculus was trying to do. Throwing the theory at me didn't do it. Applying the theory to something I enjoyed and could relate to did the trick.

Thanks again for the reference!

[torstenk]

For new and casual Modula-3 users coming across this as a search result:

Fmt.i3

Quick ref

MODULE Main;

IMPORT IO, Fmt; 
FROM Fmt IMPORT Style;

VAR fahrenheit: REAL; 

PROCEDURE FtoC(fahrenheit: REAL): REAL =
  BEGIN
    RETURN FLOAT(5) * (fahrenheit - 32.0) / FLOAT(9)
  END FtoC;

BEGIN
  IO.Put("Enter the temperature in Fahrenheit: ");
  TRY
    fahrenheit := IO.GetReal();
    IO.Put(   Fmt.Real(fahrenheit,       style := Style.Fix, prec := 1) & " F = " 
            & Fmt.Real(FtoC(fahrenheit), style := Style.Fix, prec := 1) & " C\n");
  EXCEPT IO.Error => IO.Put("Cannot read that as a floating point number, aborting.\n")
  END
END Main.

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