CVD - mkilgore/QB64pe GitHub Wiki

The CVD function decodes an 8-byte STRING generated by MKD$ (or read from a file) to DOUBLE numeric values.

result# = CVD(stringData$)

• CV functions (CVD, CVS, CVI, CVL, CVDMBF, CVSMBF) are used to convert values encoded by MK$ functions (MKD$, MKS$, MKI$, MKL$, MKDMBF$, MKSMBF$).
• Variables of numerical types are also encoded when PUT to a RANDOM or BINARY-access file.
• QB64 has _CV and _MK$ functions which can also deal with extended data types.
• DOUBLE values can range up to 15 decimal point digits. Decimal point accuracy depends on whole value places taken.

Example 1: Reading an 8-byte encoded string n$ from a file and obtaining the decoded DOUBLE value:

 '' ''
FIELD #1, 8 AS N$, 12 AS B$...
GET #1
Y# = CVD(N$) '' ''

Explanation: Reads a field from file #1, and converts the first eight bytes (N$) into an double-precision number assigned to the variable Y#.

a# = 77000.24523213
PRINT "Value of a#:"; a#
b$ = MKD$(a#)
PRINT "Value of a# encoded using MKD$: "; b$
PRINT "The string above, decoded using CVD:"; CVD(b$)

Value of a#: 77000.24523213

Value of a# encoded using MKD$: ñåxýâ╠‗@

The string above, decoded using CVD: 77000.24523213

Since the representation of a double-precision number can use up to 15 ASCII characters (fifteen bytes), writing to a file using MKD$ conversion, and then reading back with the CVD conversion can save up to 7 bytes of storage space.

• MKD$, MKI$, MKS$, MKL$, MKDMBF$, MKSMBF$
• CVI, CVS, CVL, CVSMBF, CVDMBF
• _CV, _MK$