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+---- Thread: Determine a value is INTEGER (/showthread.php?tid=2884)
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RE: Determine a value is INTEGER - TerryRitchie - 07-26-2024
(07-26-2024, 03:02 PM)Petr Wrote: I use these methods (versus the ones listed here):Thanks for the tips. I didn't even think to investigate MOD.
If Value MOD 1 = 0 -> INTEGER
If Value \ 1 = Value -> INTEGER
maybe it's the same in the background, just written differently. I didn't do this using a string conversion because those conversions are slow.
(07-26-2024, 05:25 PM)Jack Wrote: PetrMy guess is that it's slower given that division is at play. I'm going to incorporate it into my code and see the result.
I like If Value MOD 1 = 0 -> INTEGER but it remains to be tested whether it's faster or slower than using INT
integer division is rather slow especially when dealing with 64-bit integers
RE: Determine a value is INTEGER - DSMan195276 - 07-26-2024
I would consider doing something like `IF x > intval - .00001 AND x < intval + .00001 THEN` to check for an integer value, that allows for the fact that it may not always be an exact integer but is still close enough for your approximation to work. The other suggestions on this page could work for detecting if it's an exact integer value, but that's probably not what you want to do since that's the likely cause of the "hiccups" you mentioned where the value isn't actually an integer even though it "should" be.
RE: Determine a value is INTEGER - Jack - 07-26-2024
@Petr
your expression If Value MOD 1 = 0 -> INTEGER looks suspicious, in order for MOD to work it must first convert Value to Integer, I suggest that you run some tests to make sure that it's doing what you expect, I suspect that it's not
RE: Determine a value is INTEGER - Kernelpanic - 07-26-2024
@DSMan195276 - one should be able to integrate C/C++ functions using Declare . . . Can't one integrate the floor() function to determine an integer? Is that possible?
I don't have the nerve to try this out anymore. But it should work . . .
The example in C:
Code: (Select All)
//Ganzzahlwert einer eingegebenen Zahl ermitteln - 27. Juli 2024
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main (void)
{
float wert1, wert2, wert3, wert4;
printf("\nDen Ganzzahlwert einer eingegebenen Zahl ermitteln");
printf("\n==================================================");
printf("\n\nGegebene Werte: 1.6 - 1.2 - 2.8 - 2.3\n\n");
wert1 = 1.6;
wert2 = 1.2;
wert3 = 2.8;
wert4 = 2.3;
printf("Wert-1 = %.1f\n", floor(wert1));
printf("Wert-2 = %.1f\n", floor(wert2));
printf("Wert-3 = %.1f\n", floor(wert3));
printf("Wert-4 = %.1f\n", floor(wert4));
return(0);
}
RE: Determine a value is INTEGER - DSMan195276 - 07-27-2024
@KernelPanic that's possible to do with `Declare Library` but the `INT` command is actually just `std::floor` already.
RE: Determine a value is INTEGER - SMcNeill - 07-27-2024
By Golly, my over-engineered NumType will tell you if it's an integer! Exactly which types of integer it might be as well!
Code: (Select All)
CONST limit = 16
DIM test(limit) AS STRING
DATA "123a.3","-123.456","--234","1.23E15","123","dogfood","678.965","54678","-987134","1E15"
DATA "&HFF","&B1001111","&O17","&HFF&&","&B12000222","1.E-12"
FOR i = 1 TO limit
READ test(i)
NEXT
FOR i = 1 TO limit
PRINT "TEST #"; i; ": "; test(i) + " "
result = NumType(test(i))
IF result = 0 THEN PRINT "INVALID: "; NumErr$
IF result AND 1 THEN PRINT "Valid Unsigned Bit. ";
IF result AND 2 THEN PRINT "Valid Unsigned Byte. ";
IF result AND 4 THEN PRINT "Valid Unsigned Integer. ";
IF result AND 8 THEN PRINT "Valid Unsigned Long. ";
IF result AND 16 THEN PRINT "Valid Unsigned Integer64. ";
IF result AND 32 THEN PRINT "Valid Unsigned Bit. ";
IF result AND 64 THEN PRINT "Valid Signed Byte. ";
IF result AND 128 THEN PRINT "Valid Signed Integer. ";
IF result AND 256 THEN PRINT "Valid Signed Long. ";
IF result AND 512 THEN PRINT "Valid Signed Integer64. ";
IF result AND 1024 THEN PRINT "Valid Single. ";
IF result AND 2048 THEN PRINT "Valid Double. ";
IF result AND 4096 THEN PRINT "Valid Float. ";
IF result AND 8192 THEN PRINT "Valid Unsigned Offset. ";
IF result AND 16384 THEN PRINT "Valid Signed Offset. ";
PRINT
PRINT
SLEEP
NEXT
FUNCTION NumType~% (text$)
SHARED NumErr$
DIM TempNum AS INTEGER
temp$ = UCASE$(_TRIM$(text$))
NumErr$ = "": TempNum = 0
'First look for manually assigned types
r1$ = RIGHT$(temp$, 1): r = 1
r2$ = LEFT$(RIGHT$(temp$, 2), 1)
SELECT CASE r1$
CASE "`"
TestFor = 1 'bit
CASE "%"
IF r2$ = "%" THEN
r = 2
TestFor = 2 'byte
ELSE
TestFor = 3 'integer
END IF
CASE "&" 'long, int64, offset
IF r2$ = "&" THEN
r = 2
TestFor = 5 'int64
ELSEIF r2$ = "%" THEN
r = 2
TestFor = 9 'offset
ELSE
TestFor = 4 'long
END IF
CASE "!" 'single
TestFor = 6
CASE "#" 'double, float
IF r2$ = "#" THEN
r = 2
TestFor = 8 'float
ELSE
TestFor = 7 'double
END IF
CASE ELSE 'there's no set type
TestFor = 0
r = 0
END SELECT
temp$ = LEFT$(temp$, LEN(temp$) - r) 'strip off the type symbol
SELECT CASE TestFor
CASE 1 TO 5, 9
r$ = RIGHT$(temp$, 1)
IF r$ = "~" THEN Unsigned = -1: temp$ = LEFT$(temp$, LEN(temp$) - 1)
END SELECT
'check for valid prefixes
l$ = LEFT$(temp$, 2)
SELECT CASE l$
CASE "&H"
temp$ = MID$(temp$, 3)
FOR i = 1 TO LEN(temp$)
t$ = MID$(temp$, i, 1)
SELECT CASE t$
CASE "0" TO "9", "A" TO "F" 'valid
CASE ELSE
NumErr$ = NumErr$ + "Invalid Character (" + t$ + ") encountered. "
END SELECT
NEXT
IF NumErr$ <> "" THEN EXIT FUNCTION
GOTO evaluateintegers
CASE "&B"
temp$ = MID$(temp$, 3)
FOR i = 1 TO LEN(temp$)
t$ = MID$(temp$, i, 1)
SELECT CASE t$
CASE "0", "1" 'only valid bit characters
CASE ELSE
NumErr$ = NumErr$ + "Invalid Character (" + t$ + ") encountered. "
END SELECT
NEXT
IF NumErr$ <> "" THEN EXIT FUNCTION
GOTO evaluateintegers
CASE "&O"
temp$ = MID$(temp$, 3)
FOR i = 1 TO LEN(temp$)
t$ = MID$(temp$, i, 1)
SELECT CASE t$
CASE "0" TO "7" 'only valid oct characters
CASE ELSE
NumErr$ = NumErr$ + "Invalid Character (" + t$ + ") encountered. "
END SELECT
NEXT
IF NumErr$ <> "" THEN EXIT FUNCTION
GOTO evaluateintegers
END SELECT
'Test for easy integers
'First check for positive/negative values; flag for invalid cases of multiple negation.
IF MID$(temp$, 1, 1) = "-" THEN
negative = -1: temp$ = MID$(temp$, 2) 'strip off the initial negative
ELSEIF MID$(temp$, 1, 1) = "+" THEN
temp$ = MID$(temp$, 2) 'strip off the initial positive
END IF
FOR i = 1 TO LEN(temp$)
IF MID$(temp$, i, 1) = "-" THEN minus = minus + 1
IF MID$(temp$, i, 1) = "+" THEN plus = plus + 1
IF MID$(temp$, i, 1) = "." THEN period = period + 1 'Go ahead and check for multiple periods while we're at it.
IF MID$(temp$, i, 1) = "E" OR MID$(temp$, i, 1) = "D" THEN
Exponent = Exponent + 1
IF MID$(temp$, i + 1, 1) = "-" OR MID$(temp$, i + 1, 1) = "+1" THEN ExponentSign = -1
END IF
NEXT
IF period = 0 AND Exponent = 0 THEN 'we should only have integers to process
FOR i = 1 TO LEN(temp$)
t$ = MID$(temp$, i, 1)
IF t$ < "0" OR t$ > "9" THEN NumErr$ = NumErr$ + "Invalid Character (" + t$ + ") encountered. ": EXIT FUNCTION
NEXT
GOTO evaluateintegers
END IF
'At this point forward, we should only have REAL numbers to process
IF Exponent > 1 THEN NumErr$ = NumErr$ + "Multiple E/D exponent characters in string. ": EXIT FUNCTION
IF ExponentSign = 0 THEN
IF minus THEN NumErr$ = NumErr$ + "Multiple negative signs (-) encountered. ": EXIT FUNCTION
IF plus THEN NumErr$ = NumErr$ + "Multiple negative signs (-) encountered. ": EXIT FUNCTION
ELSE
IF minus > 1 THEN NumErr$ = NumErr$ + "Multiple negative signs (-) encountered. ": EXIT FUNCTION
IF plus > 1 THEN NumErr$ = NumErr$ + "Multiple negative signs (-) encountered. ": EXIT FUNCTION
END IF
IF period > 1 THEN NumErr$ = NumErr$ + "Multiple decimal points (.) encountered. ": EXIT FUNCTION
IF Exponent AND period THEN
e = INSTR(temp$, "E")
IF e = 0 THEN e = INSTR(temp$, "D")
p = INSTR(temp$, ".")
IF p > e THEN NumErr$ = NumErr$ + "Decimal points (.) AFTER E/D exponent encountered. ": EXIT FUNCTION
END IF
FOR i = 1 TO LEN(temp$)
t$ = MID$(temp$, i, 1)
SELECT CASE t$
CASE "0" TO "9", "-", "+", ".", "D", "E" 'we should have validated all these characters earlier
CASE ELSE 'so anything else is invalid
NumErr$ = NumErr$ + "Invalid Character (" + t$ + ") encountered. ": EXIT FUNCTION
END SELECT
NEXT
IF NumErr$ <> "" THEN EXIT FUNCTION
'We should've passed all the error checking by this point -- I think...
evaluateintegers:
t## = VAL(text$)
'first compare for all types
IF INT(t##) = t## THEN
IF t## = -1 OR t## = 0 THEN TempNum = TempNum OR 32 'signed bit
IF t## >= -128 AND t## <= 127 THEN TempNum = TempNum OR 64 'signed byte
IF t## >= -32768 AND t## <= 32767 THEN TempNum = TempNum OR 128 'signed integer
IF t## >= -2147483648 AND t## <= 2147483647 THEN TempNum = TempNum OR 256 'signed long
IF t## >= -9223372036854775808 AND t## <= 9223372036854775807 THEN
TempNum = TempNum OR 512 'signed integer64
TempNum = TempNum OR 16384 'signed offset
END IF
IF t## = 1 OR t## = 0 THEN TempNum = TempNum OR 1 'unsigned bit
IF t## >= 0 AND t## <= 255 THEN TempNum = TempNum OR 2 'unsigned byte
IF t## >= 0 AND t## <= 65535 THEN TempNum = TempNum OR 4 'unsigned integer
IF t## >= 0 AND t## <= 4294967295 THEN TempNum = TempNum OR 8 'unsigned long
IF t## >= 0 AND t## <= 18446744073709551615 THEN
TempNum = TempNum OR 16 'unsigned integer64
TempNum = TempNum OR 8192 'unsigned offset
END IF
END IF
IF t## >= -2.802597D45 AND t## <= 3.402823D+38 THEN
TempNum = TempNum OR 1024 'single
END IF
IF t## >= -4.490656458412465E324 AND t## <= 1.797693134862310E+308 THEN TempNum = TempNum OR 2048 'double
IF t## >= -1.18E4932 AND t## <= 1.18E+4932 THEN TempNum = TempNum OR 4096 'float
IF r THEN 'we have specific suffix; only decide if the value is valid for it
TempNum = 0
IF NOT Unsigned THEN 'unsigned
SELECT CASE TestFor
CASE 1
IF t## = -1 OR t## = 0 THEN TempNum = 32 'signed bit
CASE 2
IF t## >= -128 AND t## <= 127 THEN TempNum = 64 'signed byte
CASE 3
IF t## >= -32768 AND t## <= 32767 THEN TempNum = 128 'signed integer
CASE 4
IF t## >= -2147483648 AND t## <= 2147483647 THEN TempNum = 256 'signed long
CASE 5, 9
IF t## >= -9223372036854775808 AND t## <= 9223372036854775807 THEN
IF TestFor = 5 THEN
TempNum = 512 'signed integer64
ELSE
TempNum = 16384 'signed offset
END IF
END IF
CASE 6
IF t## >= -2.802597E-45 AND t## <= 3.402823E+38 THEN TempNum = 1024 'single
CASE 7
IF t## >= -4.490656458412465E-324 AND t## <= 1.797693134862310E+308 THEN TempNum = 2048 'double
CASE 9
IF t## >= -1.18E-4932 AND t## <= 1.18E+4932 THEN TempNum = 4096 'float
END SELECT
ELSE
SELECT CASE TestFor
CASE 1
IF t## = 0 OR t## = 1 THEN TempNum = 1 'unsigned bit
CASE 2
IF t## >= 0 AND t## <= 255 THEN TempNum = 2 'unsigned byte
CASE 3
IF t## >= 0 AND t## <= 65535 THEN TempNum = 4 'unsigned integer
CASE 4
IF t## >= 0 AND t## <= 4294967295 THEN TempNum = 8 'unsigned long
CASE 5, 9
IF t## >= 0 AND t## <= 18446744073709551615 THEN
IF TestFor = 5 THEN
TempNum = 16 'unsigned integer64
ELSE
TempNum = 8192 'unsigned offset
END IF
END IF
END SELECT
END IF
IF TempNum = 0 THEN NumErr$ = "Invalid Suffix. "
END IF
NumType = TempNum
END FUNCTION
RE: Determine a value is INTEGER - bplus - 07-27-2024
There you go @TerryRitchie Steve has an "amazing" @CR solution, just use that! LOL
Welcome back @SMcNeill I wonder if you have a story to tell from your absence?
RE: Determine a value is INTEGER - Kernelpanic - 07-27-2024
(07-27-2024, 04:30 AM)DSMan195276 Wrote: @KernelPanic that's possible to do with `Declare Library` but the `INT` command is actually just `std::floor` already.That's right, one can do that with Basic too! That's why it seemed a bit strange to me, I hadn't thought of INT.
Code: (Select All)
'Gleitkommazahl in Ganzzahligen- und Nachkommateil aufteilen - 27. Juli 2024
Option _Explicit
Dim As Double eingabe, vorKomma, nachKomma
Print
Input "Fliesskommazahl eingeben: ", eingabe
'Nachkommarest ermitteln
nachKomma = Abs(eingabe - Fix(eingabe))
'Vorkommateil, ganzzahliger Teil
vorKomma = eingabe - nachKomma
Print
Print Using "Ganzzahliger Teil: ####"; vorKomma
Print
Print Using "Nachkommateil : .###"; nachKomma
Print: Print
Print Using "Ganzzahliger Teil mit INT: ####"; Int(eingabe)
End