Convert a arithmetic expression into computed value

[jaiprasad_naidu5]

Dear All,

I have a requirement of converting a arithmetic expression into a computed value.

Example : Variable of type string will have expression as : '123 + 456 + 2'.

I want the result as 581. I tried various methods but it doesn't work.

Can any help in achieving this.

Thank you,

jp.

[vladimir_erakovic]

Hi Jaiprasad,

Try like this:

DATA: val TYPE string.

   DATA: v1(4) TYPE n,

         v2(4) TYPE n,

         v3(4) TYPE n,

         v4(4) TYPE n.

   val = '50 + 35 + 24'.

   SPLIT val AT ' + ' INTO  v1 v2 v3.

   v4 = v1 + v2 + v3.

Adjust to your needs but that's one way.

Regards,

Vladimir

[Former Member]

Hello

i have a doubt, if  i change the string input by...

val = ' 50 * 30 - 20 + 30 / 10 * ( 1 + 2 ) * 5 ' .

then how we will use your concept.

[vladimir_erakovic]

Hello Chandra,

Then we will change the concept

I don't know. This was for example in question. For that kind of equations it should be some algorithm..

Do you have some idea?

[Former Member]

No dear, I wasn't testing you, i am really looking for some logic but i think in that case we need to use some postfix/ prefix algorithm.

[SuhaSaha]

i am really looking for some logic but i think in that case we need to use some postfix/ prefix algorithm.

Unless you want to re-invent the wheel ...

[UweFetzer_se38]

Secret hint: have a look at function module "FORMULA_EVALUATION".

[SuhaSaha]

I would rather use the "internally released" EVAL_FORMULA

My 2 cents ...

[Former Member]

Hi,

you can see this example

   DATA va_string TYPE string VALUE '123 + 456 + 2'.

TYPES: BEGIN OF ty_calc,
        v1(5) TYPE n,
         END OF ty_calc.

DATA t_string TYPE TABLE OF ty_calc WITH HEADER LINE.

DATA va_sum(5) TYPE n.

START-OF-SELECTION.

REFRESH t_string.
CLEAR: t_string, va_sum.

SPLIT va_string AT '+' INTO TABLE t_string.

LOOP AT t_string.
  IF sy-tabix = 1..
    va_sum = t_string-v1.
  ELSE.
    va_sum = va_sum + t_string-v1.
  ENDIF.

ENDLOOP.

WRITE va_sum.

[jaiprasad_naidu5]

Hi Ivan,

Thanks for your reply. You logic perfectly works in case it is only addition. If the expression changes dynamically with different operators then how do we address it.

Example :

1. (123 + 456) / 654

2. (123  * 12) + 123 - 567

regards,

JP

[former_member209120]

Hi Jaiprasad Naidu  

Simple

Try like this

Data : var_final type p,
        v_len  type i.

Parameter : var type string.

Replace all OCCURRENCES OF '(' in var with ' (?'.
Replace all OCCURRENCES OF ')' in var with ' )?'.
Replace all OCCURRENCES OF '/' in var with ' /?'.
Replace all OCCURRENCES OF '+' in var with ' +?'.
Replace all OCCURRENCES OF '*' in var with ' *?'.
Replace all OCCURRENCES OF '-' in var with ' -?'.

v_len = strlen( var ).

Do v_len times.
replace '?' WITH SPACE INTO var.
enddo.
shift var LEFT DELETING LEADING SPACE.

CALL FUNCTION 'EVAL_FORMULA'
   EXPORTING
*   DEGREES                       = ' '
     formula                       = var
*   PROGRAM                       = ' '
*   ROUTINE                       = ' '
*   UNIT_OF_MEASURE               = ' '
*   NO_EXISTENCE_CHECK            = ' '
  IMPORTING
    VALUE                         = var_final
* EXCEPTIONS
*   DIVISION_BY_ZERO              = 1
*   EXP_ERROR                     = 2
*   FORMULA_TABLE_NOT_VALID       = 3
*   INVALID_EXPRESSION            = 4
*   INVALID_VALUE                 = 5
*   LOG_ERROR                     = 6
*   PARAMETER_ERROR               = 7
*   SQRT_ERROR                    = 8
*   UNITS_NOT_VALID               = 9
*   MISSING_PARAMETER             = 10
*   OTHERS                        = 11
           .
IF sy-subrc <> 0.
* MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
*         WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
ENDIF.

Write : / var_final.

[jaiprasad_naidu5]

Hi,

As Mr.Chandra said the expression would change dynamically depending upon the requirement. Few examples I would give :

1. (123 + 456) / 654

2. (123  * 12) + 123 - 567

regards,

JP

[Former Member]

Hi,

You can use this FM to remove the special characters

ES_REMOVE_SPECIAL_CHARACTER

Then you can use split command.

Code :

DATA : exp TYPE CHAR100 VALUE '(123 * 12) + 123 - 567 / 234',
       str TYPE char100.

TYPES : BEGIN OF ty_num,
        num TYPE char10,
        END OF ty_num.

DATA : i_tab TYPE TABLE OF ty_num,
       wa_tab TYPE ty_num.

START-OF-SELECTION.
CALL FUNCTION 'ES_REMOVE_SPECIAL_CHARACTER'
  EXPORTING
    text1             = exp
IMPORTING
   CORR_STRING       = str.

SPLIT str At space INTO TABLE i_tab.

LOOP AT i_tab INTO wa_tab.
If wa_tab-num eq space.
DELETE i_tab INDEX sy-tabix.
ENDIF.
ENDLOOP.

Or,

START-OF-SELECTION.
REPLACE all OCCURRENCES OF regex '[^\d]' in exp WITH '/'.

SPLIT exp At '/' INTO TABLE i_tab.

Loop again.

Hope this helps.

Regards

[Former Member]

Hi,

There is a function module available for the purpose as mentioned by Suhas Saha.

> First check for the validity of the syntax of equation using FM

     CHECK_FORMULA

> If validated then compute the equation using FM

     EVAL_FORMULA

Regards,

Ashish Rawat