Write down several useful sap Functions

Ws_download: The method for downloading a table to a local file may be efficient without classes.
Rp_last_day_of_months: the last day of the month.
Unit_conversion_simple: unit conversion
Ws_filename_get: Method of calling open dialog
C14b_add_time: add time to a certain day of the year
Bapi_currency_conv_to_internal: Convert the currency to an internal storage value.
Bapi_currency_conv_to_external: Convert the currency to an external storage value.
Conversion_exit_alpha_output: removes all the first 0 digits.
Numeric_check: determines whether it is a number.
Spell_amount: converts a number into text

Tmp_gui_file_open_dialog
Alsm_excel_to_internal_table Excel Data to internal table
Cats_numeric_input_check: Numeric check