"invalid use of member" when trying to use my function

Question

I'm trying to solve a balanced parentheses problem, here in my code I'm trying to get 1 from a function is_empty() if top of my stack is empty but then here i am stuck with this ugly error.

int is_Empty()
{
    int x=0;
    if (top==NULL)
    {
    x=1;
    }
    return x;
}

here is how i recive it

if (s1.is_Empty==1)
    {
        cout<<"matched"<<endl;
    }

my error log

bal.cpp:112:20: error: invalid use of member 'int stack::is_Empty()' (did you forget the '&' ?)        
             if (s1.is_Empty==1)
                 ~~~^~~~~~~~

Please update your question with the exact error. It would also be helpful to know more about your `top` variable. — Romen, Aug 28 '19 at 17:46
Why are you using an `int` where a `bool` would make more sense? `bool is_Empty() { return (top == NULL); }` — Remy Lebeau, Aug 28 '19 at 17:48
_@Pawan_ It looks like you coud profit from reading a [good book about the basics](https://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list). — πάντα ῥεῖ, Aug 28 '19 at 17:50

score 3 · Answer 1 · answered Aug 28 '19 at 17:46

3

if (s1.is_Empty==1)

That is not how to call a function.

Here:

if (s1.is_Empty()==1)

You may wish to review your C++ book.

answered Aug 28 '19 at 17:46

Lightness Races in Orbit

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oh i get it, the parentheses for function how silly of me , i feel like an idiot. – Pawan Nirpal Aug 28 '19 at 17:48
Yes, very silly. :) – Lightness Races in Orbit Aug 28 '19 at 17:49
Error description could also do a better job here though. I bet more people miss the `()` as a typo vs those who wanted to take the address or something that the diagnostics is saying is probably missing. I don't have a machine at hand just now but I think several languages would produce better/direct hints to just guide novices more ? It does mention invalid use of `is_Empty()` so that's a hint but it could ask if the user missed `()` later too. – ustulation Aug 28 '19 at 17:56
@ustulation I agree. – Lightness Races in Orbit Aug 28 '19 at 17:58
anyways thanks for pointing out a silly error i'll mind being more conscious about syntax then just getting carried away by the logic part ;) – Pawan Nirpal Aug 28 '19 at 17:58

"invalid use of member" when trying to use my function

1 Answers1