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+ 40

Can non-constant variables access constant functions?

Since it doesn't work the other way around, I suspect it wont work either but it would save some work if it did e.g. not having to define the same function for both const and non const.

28th May 2018, 7:12 PM
17 Answers
+ 28
This is your case. Right? const member function — add() non-constant variable — sum Edit: @ Kirk Schafer, thanks for the post, now the add() is a "const member" function ;)
29th May 2018, 3:30 PM
777 - avatar
+ 13
Yes, nonconst objects can legally call const methods.
29th May 2018, 2:52 AM
aklex - avatar
+ 9
@Rahul - I was curious about this (thanks for the code), then found a thread that says you cannot declare a non-member function const: So to check if the "const" was ignored, I copied your code into Godbolt: The output assembly is the same whether "const int ..." is there or "int ..." -- implying the const is dropped (?) ... and it does not compile (there or on SoloLearn) if const trails the function definition like a member declaration. error: non-member function 'int ...' cannot have cv-qualifier ...) const { ^~~~~ Am I missing something (clarification request)?
29th May 2018, 5:54 PM
Kirk Schafer
Kirk Schafer - avatar
+ 8
But in const functions, you can't access non-constant variables and objects
29th May 2018, 3:24 PM
Eugen Topolevski
Eugen Topolevski - avatar
+ 7
Constant Functions means that they will remain same throughout the execution of the program. Non-constant variable are those whose value can be changed at any point during the execution of the program. Therefore, Non constant variables can't be used because they change the behaviour of the function. But why do you make the function constant ? Even if you make it , Make one more function and call that constant function there and use it wisely there where you can use non-constant variable to make any number of changes you desire. Making a function constant is not a good practice. You must make only variables constant. Hope you have understood well. Even if there is any query , feel free to ask.
30th May 2018, 6:25 AM
Deepak Mittal
Deepak Mittal - avatar
+ 5
29th May 2018, 3:41 PM
Ayoub Mex
Ayoub Mex - avatar
+ 5
Rahul Nice update :) I still don't get a difference at Godbolt (in the final assembly) unless 'const' is placed after the function name: int add() const { ... } Then the assembly changes these two lines, adding "const": 23: Compute::add() const: 56: call Compute::add() const
29th May 2018, 7:43 PM
Kirk Schafer
Kirk Schafer - avatar
+ 5
@ Kirk Schafer, Thanks again! Now, it is showing the const keyword:
30th May 2018, 3:15 AM
777 - avatar
+ 3
speshal wan
29th May 2018, 8:12 PM
+ 2
of course they can. inside constant function you can decide the non constant values
29th May 2018, 7:02 PM
Alex[] - avatar
+ 2
non constant variables are functions. functions inside functions. normal. i think....
29th May 2018, 8:15 PM
Alex[] - avatar
+ 1
30th May 2018, 6:42 AM
Jude Ituma
Jude Ituma - avatar
+ 1
Yes they can
30th May 2018, 10:41 AM
Emmanuel Adu Sarpong
Emmanuel Adu Sarpong - avatar
+ 1
Напишу по русски☺
3rd Jun 2018, 9:27 PM
Ильхам Саляев
Ильхам Саляев - avatar
+ 1
24th Oct 2018, 3:14 PM
Dibyajiban Sahoo
Dibyajiban Sahoo - avatar
Yes And No. In This One, Random Times Are No.
18th Feb 2019, 3:12 AM
seth eslami
seth eslami - avatar
Fake Times Are Yes.
18th Feb 2019, 3:13 AM
seth eslami
seth eslami - avatar