Decimal Data Type (Visual Basic)
Holds signed 128-bit (16-byte) values representing 96-bit (12-byte) integer numbers scaled by a variable power of 10. The scaling factor specifies the number of digits to the right of the decimal point; it ranges from 0 through 28. With a scale of 0 (no decimal places), the largest possible value is +/-79,228,162,514,264,337,593,543,950,335 (+/-7.9228162514264337593543950335E+28). With 28 decimal places, the largest value is +/-7.9228162514264337593543950335, and the smallest nonzero value is +/-0.0000000000000000000000000001 (+/-1E-28).
Decimal data type provides the greatest number of significant digits for a number. It supports up to 29 significant digits and can represent values in excess of 7.9228 x 10^28. It is particularly suitable for calculations, such as financial, that require a large number of digits but cannot tolerate rounding errors.
The default value of
Decimal is 0.
Decimalis not a floating-point data type. The
Decimalstructure holds a binary integer value, together with a sign bit and an integer scaling factor that specifies what portion of the value is a decimal fraction. Because of this,
Decimalnumbers have a more precise representation in memory than floating-point types (
Decimaldata type is the slowest of all the numeric types. You should weigh the importance of precision against performance before choosing a data type.
Decimaldata type widens to
Double. This means you can convert
Decimalto either of these types without encountering a System.OverflowException error.
Trailing Zeros. Visual Basic does not store trailing zeros in a
Decimalliteral. However, a
Decimalvariable preserves any trailing zeros acquired computationally. The following example illustrates this.
Dim d1, d2, d3, d4 As Decimal d1 = 2.375D d2 = 1.625D d3 = d1 + d2 d4 = 4.000D MsgBox("d1 = " & CStr(d1) & ", d2 = " & CStr(d2) & ", d3 = " & CStr(d3) & ", d4 = " & CStr(d4))
The output of
MsgBoxin the preceding example is as follows:
d1 = 2.375, d2 = 1.625, d3 = 4.000, d4 = 4
Type Characters. Appending the literal type character
Dto a literal forces it to the
Decimaldata type. Appending the identifier type character
@to any identifier forces it to
Framework Type. The corresponding type in the .NET Framework is the System.Decimal structure.
You might need to use the
D type character to assign a large value to a
Decimal variable or constant. This requirement is because the compiler interprets a literal as
Long unless a literal type character follows the literal, as the following example shows.
Dim bigDec1 As Decimal = 9223372036854775807 ' No overflow. Dim bigDec2 As Decimal = 9223372036854775808 ' Overflow. Dim bigDec3 As Decimal = 9223372036854775808D ' No overflow.
The declaration for
bigDec1 doesn't produce an overflow because the value that's assigned to it falls within the range for
Long value can be assigned to the
The declaration for
bigDec2 generates an overflow error because the value that's assigned to it is too large for
Long. Because the numeric literal can't first be interpreted as a
Long, it can't be assigned to the
bigDec3, the literal type character
D solves the problem by forcing the compiler to interpret the literal as a
Decimal instead of as a