How to display a float number in scientific?

[desA]

Good evening everyone,

I would like display a float number in scientific mode to a set number of decimal places - for display printout purposes. 

E.g.  12345.6 -> 1.23E4

Please advise the appropriate command/s to do this in qb64pe. 

Many thanks... 

[Kernelpanic]

For example:

Code: (Select All)

Print Using "##.##^^^^"; 12345.6

Print Using

[bplus]

I am curious

Code: (Select All)

Print Using "##.##^^^^"; 12345.6789123

What do those "^"'s do?

[Pete]

I am curious

Code: (Select All)

Print Using "##.##^^^^"; 12345.6789123

What do those "^"'s do?

They are tin foil hats to keep aliens from viewing your output!

Actually: ^^^^ tells PRINT USING to print the answer in exponential format.

Pete

[Kernelpanic]

As Pete has already written. Five ^ results in a three-digit exponent output - but then it's over. Sex is no longer acceptable! 

Code: (Select All)

Dim As Double a



a = 12345.6

Print Using "##.##^^^^"; a

Print Using "##.##^^^^"; 12345.6



Print Using "##.##^^^^^"; 12345.6

[Pete]

As Pete has already written. Five ^ results in a three-digit exponent output - but then it's over. Sex is no longer acceptable! 

Code: (Select All)

Dim As Double a



a = 12345.6

Print Using "##.##^^^^"; a

Print Using "##.##^^^^"; 12345.6



Print Using "##.##^^^^^"; 12345.6

That's why I avoid PRINT USING, so I don't miss out on 'sex'.

I'm not sure what my latest string math post was, but I think this post included my way to convert to SI without using PRINT USING.

https://qb64phoenix.com/forum/showthread...36#pid5236

Pete

[Kernelpanic]

I'm not sure what my latest string math post was, but I think this post included my way to convert to SI without using PRINT USING.

Yes, that's right! It works, programming-wise is it great, but what effort is involved . . .?

[Jack]

Code: (Select All)

Declare Library

    Function snprintf& (Dest As String, Byval l As Long, frmt As String, Byval x As _Float)

End Declare



Dim As String * 20 result

Dim As String format

Dim As Long resultlen, flag

Dim As Single x



resultlen = Len(result) - 1

result = Space$(resultlen) + Chr$(0)

format = "%.2e" + Chr$(0)

x = 12345.6

flag = snprintf&(result, resultlen, format, x)

Print result



result = Space$(resultlen) + Chr$(0)

format = "%12.2e" + Chr$(0)

x = 12345.6

flag = snprintf&(result, resultlen, format, x)

Print result

[Kernelpanic]

@Jack - It works and is not as complicated as Pete's solution. - A saying comes to mind:

Why do it simply when one can do it complicated?  

Code: (Select All)

'Umrechnung Dezimalzahl in Exponentialschreibweise - 4. Aug. 2024

'Referenz S.263 - Print Using Formatierungssymbole



Option _Explicit



'Bei Double erscheint ein "D" statt "E"

Dim As Single x, z



Locate 2, 3

Print "Dezimalzahl in Exponentialdarstellung"

Locate 3, 3

Print "====================================="



Locate 5, 3

Input "Dezimalzahl        : ", x



Locate 6, 3

Print Using "Als Exponentialzahl: ##.##^^^^"; x



Locate 8, 3

Input "Weitere Dezimalzahl: ", z



Locate 9, 3

'5 Exponentialsymbole ^ bewirken dreistellige Ausgabe des Exponenten

Print Using "Als Exponentialzahl: ##.##^^^^^"; z



End

PS: I didn't find snprintf() in my C books, only here: snprintf()

[Pete]

Well guys, the whole idea behind BASIC is to figure out how to code it from scratch. PRINT USING relies on a builtin library, and Jack's neat example is a C library; so you really cannot ascertain matters of complexity when you are not really looking under the hood.

Pete