Function modules: Amount and Currency

• CURRENCY_AMOUNT_SAP_TO_IDOC - Convert currency to IDOC format
• CONVERT_TO_LOCAL_CURRENCY - Conversion of currency
• CLOI_PUT_SIGN_IN_FRONT Move the negative sign from the left hand side of a number, to the right hand side of the number. Note that The result will be left justified (like all
  character fields), not right justified as numbers normally are.
• CONVERT_TO_FOREIGN_CURRENCY Convert local currency to foreign currency.
• CONVERT_TO_LOCAL_CURRENCY Convert from foreign currency to local currency

Example 1: Convert amount to/from string

Amount to string:

CALL FUNCTION 'HRCM_AMOUNT_TO_STRING_CONVERT'
 EXPORTING
   betrg                         = 3000
   WAERS                         = 'DKK'
*   NEW_DECIMAL_SEPARATOR         =
*   NEW_THOUSANDS_SEPARATOR       =
 IMPORTING
  STRING                        =  slam.

String to amount:

CALL FUNCTION 'HRCM_STRING_TO_AMOUNT_CONVERT'
 EXPORTING
   string                    = slam2
   DECIMAL_SEPARATOR         = '.'
*   THOUSANDS_SEPARATOR       =

   WAERS                     = 'HUF'
IMPORTING
  BETRG                     = b2
* EXCEPTIONS
*   CONVERT_ERROR             = 1
*   OTHERS                    = 2.


source :http://erpgenie.com/utilities/1155-function-modules-amount-and-currency