CByte

[Frank Brübach]

Hello Charles, do you know cByte?
Its interesting datatype for oxygen too? Its existing in freebasic as converting Data Type

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CBYTE
Converts numeric or string expression to Byte.

Syntax:
declare function Cbyte ( byval expression as datatype ) as byte

Type typename
declare operator cast ( ) as byte
End Type

Usage:
result = Cbyte( numeric expression )
result = Cbyte( string expression )
result = Cbyte( user defined type )

Parameters:
expression
A numeric, string, or pointer expression to cast to a Byte value.
datatype
Any numeric, string, or pointer data type.
typename
A user defined type.

Return Value:
A Byte value.

Description:
The Cbyte function rounds off the decimal part and returns a 8-bit Byte value. The function does not check for an overflow, and results are undefined for values which are less than -128 or larger than 127.

The name can be explained as 'Convert to Byte'.

If the argument is a string expression, it is converted to numeric by using Valint.

Examples:
' Using the CBYTE function to convert a numeric value

'Create an BYTE variable
Dim numeric_value As Byte

'Convert a numeric value
numeric_value = CByte(-66.30)

'Print the result, should return -66
Print numeric_value
Sleep


[Charles Pegge]

Hi Frank,

string-to-number conversion etc is built into Oxygen:

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sbyte sb 'signed byte
sb=32
print sb
sb=32.6
print sb 'rounds to 33
sb="-32"
print sb 'auto-convert string -32
sb=255
print sb 'wrap overflow -1


[Frank Brübach]

Oh good didn't know yet thx Charles

Found an old freebasic examples with cByte(260)=4 and I didnt understand the result but now...

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''CodeSelect
sbyte sb 'signed byte
sb=32
print sb
sb=32.6
print sb 'rounds to 33
sb="-32"
print sb 'auto-convert string -32
sb=255
print sb 'wrap overflow -1
' if that's -1 then 260 it's 4 ?
' why it's 4 as result? => 5 - 1 ? = 4
sb=260
print sb ' 4


[Charles Pegge]

some signed byte values:

0x7f -->  127
0x80 --> -128
0x81 --> -127
...
0xfe --> -2
0xff --> -1

0x104 modulo 0xff --> 4