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= Numbers =
{{OOo}} Basic supports five basic types for processing numbers:

* Integer
* Long Integer
* Float
* Double
* Currency

== Integer Variables ==

Integer variables can store any whole number between '''-32768''' and '''32767'''. An integer variable can take up to two bytes of memory. The type declaration symbol for an integer variable is <tt>%</tt>. Calculations that use integer variables are very fast and are particularly useful for loop counters. If you assign a floating point number to an integer variable, the number is rounded up or down to the next whole number.

Example declarations for integer variables:

 Dim Variable As Integer
 Dim Variable%

== Long Integer Variables ==

Long integer variables can store any whole number between '''–2147483648''' and '''2147483647'''. A long integer variable can takes up to four bytes of memory. The type declaration symbol for a long integer is <tt>&</tt>. Calculations with long integer variables are very fast and are particularly useful for loop counters. If you assign a floating point number to a long integer variable, the number is rounded up or down to the next whole number.

Example declarations for long integer variables:

 Dim Variable as Long
 Dim Variable&

== Single Variables ==

Single variables can store any positive or negative floating point number between '''3.402823 x 10<sup>38</sup>''' and '''1.401298 x 10<sup>-45</sup>'''. A single variable can take up to four bytes of memory. The type declaration symbol for a single variable is <tt>!</tt>.

Originally, single variables were used to reduce the computing time required for the more precise double variables. However, these speed considerations no longer apply, reducing the need for single variables.

Example declarations for single variables:

 Dim Variable as Single
 Dim Variable!

== Double Variables ==

Double variables can store any positive or negative floating point numbers between '''1.79769313486232 x 10<sup>308</sup>''' and '''4.94065645841247 x 10<sup>-324</sup>'''. A double variable can take up to eight bytes of memory. Double variables are suitable for precise calculations. The type declaration symbol is <tt>#</tt>.

Example declarations of double variables:

 Dim Variable As Double
 Dim Variable#

== Currency Variables ==

Currency variables differ from the other variable types by the way they handle values. The decimal point is fixed and is followed by four decimal places. The variable can contain up to 15 numbers before the decimal point. A currency variable can store any value between '''—922337203685477.5808''' and '''+922337203685477.5807''' and takes up to eight bytes of memory. The type declaration symbol for a currency variable is <tt>@</tt>.

Currency variables are mostly intended for business calculations that yield unforeseeable rounding errors due to the use of floating point numbers.

Example declarations of currency variables:

 Dim Variable As Currency
 Dim Variable@

== Specification of Explicit Numbers ==

Numbers can be presented in several ways, for example, in decimal format or in scientific notation, or even with a different base than the decimal system. The following rules apply to numerical characters in {{OOo}} Basic:

=== Whole Numbers ===

The simplest method is to work with whole numbers. They are listed in the source text without a comma separating the thousand figure:

 Dim A As Integer
 Dim B As Float
 
 A = 1210
 B = 2438

The numbers can be preceded by both a plus (+) or minus (-) sign (with or without a space in between):

 Dim A As Integer
 Dim B As Float
 
 A = + 121
 B = - 243

=== Decimal Numbers ===

When you type a decimal number, use a period (.) as the decimal point. This rule ensures that source texts can be transferred from one country to another without conversion.

 Dim A As Integer
 Dim B As Integer
 Dim C As Float
 
 A = 1223.53      ' is rounded
 B = - 23446.46   ' is rounded
 C = + 3532.76323

You can also use plus (+) or minus (-) signs as prefixes for decimal numbers (again with or without spaces).

If a decimal number is assigned to an integer variable, {{OOo}} Basic rounds the figure up or down.

=== Exponential Writing Style ===

{{OOo}} Basic allows numbers to be specified in the exponential writing style, for example, you can write <tt>1.5e-10</tt> for the number '''1.5 x 10<sup>-10</sup>''' (0.00000000015). The letter "e" can be lowercase or uppercase with or without a plus sign (+) as a prefix.

Here are a few correct and incorrect examples of numbers in exponential format:

 Dim A As Double
 
 A = 1.43E2    ' Correct
 A = + 1.43E2  ' Correct (space between plus and basic number)
 A = - 1.43E2  ' Correct (space between minus and basic number)
 A = 1.43E-2   ' Correct (negative exponent)
 A = 1.43E -2  ' Incorrect (spaces not permitted within the number)
 A = 1,43E-2   ' Incorrect (commas not permitted as decimal points)
 A = 1.43E2.2  ' Incorrect (exponent must be a whole number)

Note, that in the first and third incorrect examples that no error message is generated even though the variables return incorrect values. The expression

 A = 1.43E -2

is interpreted as 1.43 minus 2, which corresponds to the value -0.57. However, the value 1.43 * 10<sup>-2</sup> (corresponding to 0.0143) was the intended value. With the value

 A = 1.43E2.2

{{OOo}} Basic ignores the part of the exponent after the decimal point and interprets the expression as

 A = 1.43E2

=== Hexadecimal Values ===

In the hexadecimal system (base 16 system), a 2-digit number corresponds to precisely one byte. This allows numbers to be handled in a manner which more closely reflects machine architecture. In the hexadecimal system, the numbers 0 to 9 and the letters A to F are used as numbers. An A stands for the decimal number 10, while the letter F represents the decimal number 15. {{OOo}} Basic lets you use whole numbered hexadecimal values, so long as they are preceded by <tt>&H</tt>.

 Dim A As Long
 A = &HFF ' Hexadecimal value FF, corresponds to the decimal value 255
 A = &H10 ' Hexadecimal value 10, corresponds to the decimal value 16

=== Octal Values ===

{{OOo}} Basic also understands the octal system (base 8 system), which uses the numbers 0 to 7. You must use whole numbers that are preceded by <tt>&O</tt>.

 Dim A As Long
 A = &O77 ' Octal value 77, corresponds to the decimal value 63
 A = &O10 ' Octal value 10, corresponds to the decimal value 8