Call by reference and Changing

[Former Member]

Hi all,

Can anybody tell me what is difference between Call by reference and Changing parameters.

good help will be rewarded

Sachin.

[Vijay]

hi sachin

<b>Call by reference</b>: actaul parameters are passed, no formal parameters exist.

<b>Changing parameters</b>: pass by value, actaul parameters are passed to formal parameters , temporary memeory allocated to formal parameters

please <b>Go thru this link it will help you a lot.</b>

http://help.sap.com/saphelp_nw2004s/helpdata/en/9f/db984635c111d1829f0000e829fbfe/content.htm

regards

vijay

<b>plz dont forget to reward if useful</b>

[Former Member]

TRY this as it is giving error bcoz of no ACTUAL parameters.

Pls correct me if i am wrong.

DATA: num1 TYPE i,

num2 TYPE i,

sum TYPE i.

num1 = 2. num2 = 4. sum = 0.

PERFORM expRef USING num1 num2.

FORM expRef.

data: add_sum type i.

add_sum = num1 + num2.

write: / 'Sum is:',add_sum.

ENDFORM

[Vijay]

hi sachin

here is ur correct code

DATA: num1 TYPE i,
num2 TYPE i,
sum TYPE i.

num1 = 2. num2 = 4. sum = 0.
PERFORM expRef USING num1 num2.


FORM expRef using p_num1 p_num2.
data: add_sum type i.
add_sum = p_num1 + p_num2.
write: / 'Sum is:',add_sum.
ENDFORM.

regards

vijay

<b>plz dont forget to reward points if helpful</b>

[Former Member]

Hi vijay,

That means in pass by reference we need to send formal parameters.

sachin

[Vijay]

hi sachin

<b>no its not like that. in pass by reference the address of the variables are copied not the value . in this example the address of these varables num1 and num2 gets copied to

p_num1 and p_num2. thatswhy it is pass by reference</b>

hope it clears ur doubt

regards

vijay

<b>plz dont forget to reward points if useful</b>

[Vijay]

hi sachin

is there any problem.

please close the thread if answered and reward points accordingly.

[Former Member]

Hi Vijay,

I am not been able to reward points. SDN is giving error while assigning.

Sachin

[Vijay]

HI SACHIN

<b>keep trying but please dont forget :):):):)</b>

<b>and <b>one more thing to clear ur doubt</b>. you change the values of p_num1 and p_num2 in form endform. u see the value of num1 and num2 gets chenged which wont happen at all if it is pass by value . so its clear that its pass by reference.</b>

EXAMPLE

DATA: num1 TYPE i,
num2 TYPE i,
sum TYPE i.

num1 = 2. num2 = 4. sum = 0.
PERFORM expRef USING num1 num2.
write: / num1 , num2.

FORM expRef using p_num1 p_num2.
data: add_sum type i.
add_sum = p_num1 + p_num2.
p_num1 = 3.
p_num2 = 5.

write: / 'Sum is:',add_sum.
ENDFORM.

regards

vijay

[Vijay]

hi

i guess there are 3 options while assigning points

thnx anyways..