CDbl Function

CDbl Function

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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

CSng Function