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29 lines
1.1 KiB
Markdown
29 lines
1.1 KiB
Markdown
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[DOUBLE](DOUBLE) type floating point numerical values use 8 bytes per value.
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## Syntax
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> [DIM](DIM) variable [AS](AS) [DOUBLE](DOUBLE)
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## Description
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* Literal or variable values can range up to 15 decimal point places.
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* The variable suffix type is **#**.
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* Use DOUBLE and [_FLOAT](_FLOAT) variables sparingly as they use a lot of program memory.
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* Values returned may be expressed using exponential or [scientific notation](scientific-notation) using **E** for SINGLE or **D** for DOUBLE precision.
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* Floating decimal point numerical values cannot be [_UNSIGNED](_UNSIGNED).
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* Values can be converted to 8 byte [ASCII](ASCII) string values using [_MKD$](_MKD$) and back with [_CVD](_CVD).
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* **When a variable has not been defined or has no type suffix, the value defaults to [SINGLE](SINGLE).**
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* **Warning: QBasic keyword names cannot be used as numerical variable names with or without the type suffix.**
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## QBasic
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* Results of mathematical calculations may be approximate or slow in QuickBASIC 4.5.
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## See Also
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* [DIM](DIM), [DEFDBL](DEFDBL)
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* [MKD$](MKD$), [CVD](CVD)
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* [SINGLE](SINGLE), [_FLOAT](_FLOAT)
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* [LEN](LEN)
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* [Variable Types](Variable-Types)
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