Programming Gambas from Zip/DataTypes

Data Types and Conversions edit

Data Types edit

One byte is the amount of memory required to store a single character such as the letter “A” or the digit “1”. It is eight bits (1’s or 0’s, like little switches that are on or off, up or down). 8 bits = 1 byte. 4 bits = 1 nibble, but that one is not used much.

Description and Limits Default value Size in memory
Boolean True or false FALSE 1 byte
Byte 0 to 255 0 1 byte
Short -32,768 to +32,767 0 2 bytes
Integer -2,147,483,648 to +2,147,483,647 0 4 bytes
Long -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 0 8 bytes
Single Single precision 0.0 4 bytes
Float Floating point or double precision 0.0 8 bytes
Date Date and time, each stored in an integer. NULL 8 bytes
String A variable length string of characters. NULL 4 bytes on 32 bits systems, 8 bytes on 64 bits systems
Variant Any datatype. NULL 12 bytes on 32 bits systems, 16 bytes on 64 bits systems
Object Anonymous reference to any object. NULL 4 bytes on 32 bits systems, 8 bytes on 64 bits systems.
Pointer A memory address. 0 4 bytes on 32 bits systems, 8 bytes on 64 bits systems

Conversions edit

Some conversions are omitted. Many of these conversions are done automatically as required. For example, these are fine without explicitly having to write the functions:

label1.text = 54.65

Dim d As Date = "09/06/1972 01:45:12"

Dim d As Date = 2484515 gives d the date 05/16/2002
CBool to a Boolean An expression is false if it is
  • A false boolean
  • A zero number
  • A zero length string
  • A null date
  • A null object

CBool(0) is false

CBool(1) is true

CBool("Gambas") is true

CBool("") is false

CBool(Null) is false

0 → False; Anything else → True

e.g. 6 is True; -4 is True; 3-(1+2) is False.

CDate to a Date CDate("09/06/1972 01:45:12")


CFloat or CFlt to a Float CFloat("+3.1416")

Cfloat("1.0E+3") is 1000

CInt or CInteger to an Integer CInt("17") is the number 17

CInt(True) is -1

CInt(Now) is 2490779

CInt(3.2) is 3

CInt(3.9) is 3

CInt(6) is 6

CInt(-7.2) is -7

CInt(-7.9) is -7

TRUE → -1 FALSE → 0

CStr or CString to a String CStr(-1972) is -1972

CStr(Now) is 05/16/2002 15:08:31

CStr(Pi) is 3.14159265359

Str a number or a date into a string The opposite of Val()

Use Format() to have control of what form the number or date takes.

Val a string into a number or a date Conversion follows these steps until if finds something it can convert:

Look for a date

Look for a long

Look for an integer

Look for a true or false

If none, return NULL.

IsNull(Val("Gambas")) is True

Programming Gambas from Zip
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