Name
CDbl Function
Named Arguments
No
Syntax
CDbl(expression
)
-
expression
(required; Numeric or String) -1.79769313486232E308 to -4.94065645841247E-324 for negative values, and 4.94065645841247E-324 to 1.79769313486232E308 for positive values
Return Value
expression
cast as a Double data type
Description
Converts expression
to a Double data type
Rules at a Glance
If the value of
expression
is outside the range of the double data type, an overflow error is generated.expression
must evaluate to a numeric value; otherwise, a type-mismatch error is generated.
Example
Dim dblMyNumber as Double If IsNumeric(sMyNumber) then dblMyNumber = CDbl(sMyNumber) End If
Programming Tips and Gotchas
When converting a string representation of a number to a numeric value, the data type conversion functions, such as CDbl, are preferable to the older function, Val. This is because the data type conversion functions take account of the system’s regional settings, whereas Val recognizes only the period as a decimal separator. For example, if a user inputs a value of 6,231,532.11, CDbl correctly converts it to a double with a value of 6231532.11, while Val returns a value of 6.
Use IsNumeric to test whether
expression
evaluates to a number.Like most conversion functions, CDbl is not actually a function in the Microsoft. VisualBasic namespace. Instead, it is similar to a Visual C++ macro; the compiler translates the function call into inline code.
See Also
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