Pass by value - actual parameter is not changing

Updated May 18, 2018

hi gurus,

data : a type i value '4',
b type i value '4',
c type i value '4'.

write : / c.

perform add using a b changing c.

write : / 'outside' , c.

form add using a1 b1 changing value(c1).

c1 = a1 + b1.
write : 'c1' , c1.

endform.

in this pgm , why the actual parameter is not changing , its returning only the formal parameter value..

Comments

08 Jan 2014 5:27 am nandana ramesh Best Answer

Hi,

the values is changing because of the keyword CHANGING in the definition of the subroutine. Instead use the below code

data : a type i value '4',
b type i value '4',
c type i value '4'.

write : / c.

perform add using a b c."changing c.

write : / 'outside' , c.

form add using a1 b1 value(c1). "changing value(c1).
c1 = a1 + b1.
write : 'c1' , c1.

endform.

this would answer your question.

regards,

Nandana

20 Aug 2008 11:51 am Shalesh Singh Visen
Hi.

If the output that we r getting is:-
4
c1 8
outside 8

then its because we are using CHANGING VALUE().
When CHANGING VALUE() is used the value of the actual parameter remains the same inside the FORM...ENDFORM statements.
But if u refer to the actual parameter once control passes beyond the ENDFORM statement, the actual parameter will give u the value of the then formal parameter.

Catch this:

data : a type i value '4',
b type i value '4',
c type i value '4'.
write : / c.
** will write c = 4

perform add using a b changing c.
**go to the FORM statement

write : / 'outside' , c.
** and this will write c = c1 = 8.

form add using a1 b1 changing value(c1).

c1 = a1 + b1.
write : 'c1' , c1.
** will write c1 = 8 but

write : 'c' , c.
** will write c = 4.

endform.
Hope this clears Ur doubt.

Regards.
Vipin Varghese.