Conversions

Currency Module User's Guide
Rogue Wave web site: Home Page | Main Documentation Page

6.7 Conversions

Constructors and conversion functions provide conversion from and to various types. The most common conversions are from an int, a string, or a double to an RWDecimal<T>, or from an RWDecimal<T> to an int, a double, or a string. Conversions between RWDecimal<T> types are also provided.

6.7.1 Conversion from Integers and Strings

Conversions to RWDecimal<T> objects are provided by the constructors

RWDecimal<T>(long int);
RWDecimal<T>(const char*);

These functions produce an exact representation of the argument. The string constructor accepts strings with embedded commas and a leading dollar sign. Negative numbers may be indicated either with a minus sign or by parentheses. A technical description of the exact grammar allowed is given in the "Technical Notes" section of this manual.

6.7.2 Conversion from Built-In Floating Point

The Currency Module does not automatically provide conversion from a built-in floating point number to an RWDecimal<T> because such conversions often cause round-off errors. This situation occurs frequently with constants. For example, the following code

RWDecimal<RWMP2Int> x = 1.01;

will not produce an exact representation of 1.01, since the compiler interprets the constant as a floating point literal. To set x to an exact representation of 1.01, you can use a string or the form of the constructor that takes an integer and a number of decimal places. For example:

RWDecimal<RWMP2Int> x = "1.01"

RWDecimal<RWMP2Int> x(101,2);

If you do want to convert from a floating point number, use the global function.

RWDecimal<T> from(long double)

This will return a decimal object approximately equal to the parameter.

6.7.3 Conversion to Built-In Types

Conversions from RWDecimal objects are provided by the functions:

RWCString toString(const RWDecimal<T>&)
long double toDouble(const RWDecimal<T>&)
long int toInt(const RWDecimal<T>&)

Conversion to a string is exact but, conversion to a long double will likely involve rounding. Conversion to a long int will only produce a meaningful result if the number will fit in an integer.

The Rogue Wave name and logo, and SourcePro, are registered trademarks of Rogue Wave Software. All other trademarks are the property of their respective owners.
Provide feedback to Rogue Wave about its documentation.