PDS(7.1) Procedures: Difference between revisions

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QB64 was created to be compatible with Quick Basic 4.5 only as it was the most popular version. The following sub-procedures have been created to do things that were available in PDS versions of Quick Basic 7.0 and 7.1.
QB64 was created to be compatible with Quick Basic 4.5 only as it was the most popular version. The following sub-procedures have been created to do things that were available in PDS versions of Quick Basic 7.0 and 7.1.


== CURRENCY ==
== CURRENCY ==


=== MKC$ ===
=== MKC$ ===
Line 80: Line 80:


<p style="text-align: center">([[#toc|Return to Table of Contents]])</p>
<p style="text-align: center">([[#toc|Return to Table of Contents]])</p>


== DIR$ ==
== DIR$ ==

Revision as of 10:41, 29 January 2023

QB64 was created to be compatible with Quick Basic 4.5 only as it was the most popular version. The following sub-procedures have been created to do things that were available in PDS versions of Quick Basic 7.0 and 7.1.


CURRENCY

MKC$

PDS could use the CURRENCY variable type and had the MKC$ function to convert those values to 8 byte ASCII string values. QB64 can convert _FLOAT currency amounts to strings using _MK$ with _INTEGER64 values:

SCREEN 12
DIM value AS _FLOAT
value = 12345678901234.6789 '    any currency value with up to 4 decimal point places

_PRINTSTRING (1, 50), "[" + MKC$(value) + "]" ' show ASCII string value

END

FUNCTION MKC$ (CurrVal AS _FLOAT) 'converts currency amount to PDS or VB currency string
    DIM CVal AS _INTEGER64
    CVal = CurrVal * 10000 '        multiply float value by 10 thousand
    MKC = _MK$(_INTEGER64, CVal)
END FUNCTION
Note: The _FLOAT currency amount must be multiplied by 10000 before it is converted to the ASCII string value.

CVC

PDS also had the CVC function to convert MKC$ currency string values back to currency amounts. QB64 can use _CV with _INTEGER64 to convert those 8 byte values back to _FLOAT currency values. The procedure gets the currency string from a file:

SCREEN 12
DIM currency AS STRING * 8
OPEN "Currency.bin" FOR BINARY AS #1 'binary file with MKC$ values created by PDS or VB
GET #1, , currency
CLOSE #1

_PRINTSTRING (1, 10), "[" + currency + "]" 'show ASCII string value from file

_PRINTSTRING (1, 30), STR$(CVC##(currency))

END

FUNCTION CVC## (CurrStr AS STRING) 'converts currency string to a _FLOAT currency amount
    DIM CV AS _INTEGER64
    CV = _CV(_INTEGER64, CurrStr)
    CVC = CV / 10000 '                   divide by 10 thousand
END FUNCTION
Note: The _FLOAT currency amount must be divided by 10000 to create up to 4 decimal point places.

PUT

Currency values can be PUT directly into BINARY or RANDOM files using an _INTEGER64 variable value.

DIM curr AS _INTEGER64, currency AS _FLOAT

currency = 9876.543
curr = currency * 10000 ' multiply currency value by 10000

OPEN "currency.bin" FOR BINARY AS #1 ' a binary file to hold PDS currency values
PUT #1, , curr
CLOSE #1

END

GET

When currency values are PUT directly into a BINARY or RANDOM file, _INTEGER64 can GET them directly. Then divide by 10 ^ 4:

DIM curr AS _INTEGER64, currency AS _FLOAT
OPEN "currency.bin" FOR BINARY AS #1 ' any binary file holding PDS currency values
GET #1, , curr
CLOSE #1

currency = curr / 10000 ' use any floating decimal point type within currency range

PRINT currency

END
Note: The currency value can be any SINGLE, DOUBLE or _FLOAT floating decimal point value that will hold the range of values.


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DIR$

Not to be confused with QB64's _DIR$ function.

This PDS(7.1) derived DIR$ function returns a filename or a list when more than one exist. The file spec can use a path and/or wildcards.

FOR i = 1 TO 2
    PRINT
    LINE INPUT "Enter a file spec: ", spec$
    file$ = DIR$(spec$) 'use a file spec ONCE to find the last file name listed
    PRINT DIRCount%, file$, 'function can return the file count using SHARED variable
    IF DIRCount% > 1 THEN
        DO
            K$ = INPUT$(1)
            file$ = DIR$("") 'use an empty string parameter to return a list of files!
            PRINT file$,
        LOOP UNTIL LEN(file$) = 0 'file list ends with an empty string
    END IF
NEXT

END

FUNCTION DIR$ (spec$)
    CONST TmpFile$ = "DIR$INF0.INF", ListMAX% = 500 'change maximum to suit your needs
    SHARED DIRCount% 'returns file count if desired. MAY conflict with user's existing code
    STATIC Ready%, Index%, DirList$()
    IF NOT Ready% THEN REDIM DirList$(ListMAX%): Ready% = -1 'DIM array first use
    IF spec$ > "" THEN 'get file names when a spec is given
        SHELL _HIDE "DIR " + spec$ + " /b > " + TmpFile$
        Index% = 0: DirList$(Index%) = "": ff% = FREEFILE
        OPEN TmpFile$ FOR APPEND AS #ff%
        size& = LOF(ff%)
        CLOSE #ff%
        IF size& = 0 THEN KILL TmpFile$: EXIT FUNCTION
        OPEN TmpFile$ FOR INPUT AS #ff%
        DO WHILE NOT EOF(ff%) AND Index% < ListMAX%
            Index% = Index% + 1
            LINE INPUT #ff%, DirList$(Index%)
        LOOP
        DIRCount% = Index% 'SHARED variable can return the file count
        CLOSE #ff%
        KILL TmpFile$
    ELSE IF Index% > 0 THEN Index% = Index% - 1 'no spec sends next file name
    END IF
    DIR$ = DirList$(Index%)
END FUNCTION
Code by Ted Weissgerber
Explanation: The function will verify that a file exists (even if it is empty) by returning it's name or it returns an empty string if no file exists. It can return a list of file names by using an empty string parameter("") after sending a wildcard spec to get the first file name. The number of file names found is returned by using the SHARED variable, DIRCount%. Unlike the PDS DIR$ function, it MUST use an empty string parameter until QB64 supports optional parameters! The function does NOT delete empty files.


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