Why does my return not work in display function?

[ruby berry]

I'm trying to return my display but not sure what this error message means in my context. "ERROR: Initial value of reference to non-const must be lvalue" !solved

[errant sequoia]

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[proven salmon]

Your function should return std::ostream&, but this has type Ticket*

You probably wanted to make ostream the parameter of the function and use it instead of cout

std::ostream& Ticket::display(std::ostream& outStream) const
{
    outStream << "<Put whatever you want to print here>";    

    return outStream;
}

[minor hamlet]

You can also do return *this

[ruby berry]

i tried that but get this error

[minor hamlet]

Wait what are you trying to return here

[modest yarrow]

I suspect you really meant to make this a void function and not return anything.

[unreal beacon]

cause you shouldn't return this

this is completly wrong

look at the code Sixshaman shows

returning this will never work here....

[unreal beacon]

no you can't.....

[ruby berry]

When I try the code sixshaman shows it asks for arguments now in my main

[unreal beacon]

well yeah of it doesn't work?

ugh wait

2 awnsers are mixing things

from the original post I thought you where traing to overload the operator<< for some reason

[ruby berry]

If i try this it says its oustream is undefines and type name is not allowed

i am

this is code before it

[unreal beacon]

wait you are trying to overload operator<< or trying to print things to console?

cause those are very diffent things

[ruby berry]

trying to overload

[unreal beacon]

okay then yeah your current syntax is completly wrong

std::ostream& operator<<(std::ostream& os, const T& obj)
{
    // write obj to stream
    return os;
}

is the overload operator

// overload_date.cpp
// compile with: /EHsc
#include <iostream>
using namespace std;

class Date
{
    int mo, da, yr;
public:
    Date(int m, int d, int y)
    {
        mo = m; da = d; yr = y;
    }
    friend ostream& operator<<(ostream& os, const Date& dt);
};

ostream& operator<<(ostream& os, const Date& dt)
{
    os << dt.mo << '/' << dt.da << '/' << dt.yr;
    return os;
}

int main()
{
    Date dt(5, 6, 92);
    cout << dt;
}

from the ms docs

if you want to avoid the friend function and make it a member I believe the proper definition is:
std::ostream& operator<<(std::ostream& os);

[ruby berry]

I have to use the display function though

[unreal beacon]

why?

[ruby berry]

It's required by my professor

the overload function above the display was given by my professor I just need to figure out the display

[unreal beacon]

then this is not the way..... for operator overloading....

ima need more context then

[ruby berry]

I can give all my code or the instructions of what im trying to accomplish

So i have to return the details of the ticket after checking with if statement

[unreal beacon]

ooooooooooh

man, that is dumb

[ruby berry]

yea you can credit my godlike prof

[unreal beacon]

then just construct a local std::osstream object and return that and write to the ossstream

the 2nd point is iffy at best as well

anyhow

[ruby berry]

how would I go about doing that

[unreal beacon]

similar to what you have now realy

but instead of writing to cout write to the local osstream

[minor hamlet]

Yeah not here, my bad
But usually you would do that when overloading operator<< when you output something

[unreal beacon]

not realy as it's for IO so you would return the osstream and not the local object

[minor hamlet]

https://en.cppreference.com/w/cpp/io/basic_ostream/operator_ltlt

[unreal beacon]

yeah and that returns a ostream....

returning *this would return the local object

[ruby berry]

do you mean like this?

[unreal beacon]

no, that is doing the exact oposite of what I said.....

create a local ostream variable

then write to that, and at the end return that

[ruby berry]

How do I create a local ostream variable for it

[unreal beacon]

hu this is fucking hillarious....

after further looking into things im pretty sure you actually can't make local osstream

what makes this 100% hillarious cause that means the exercise is idiotic

[ruby berry]

yea we dont really get a lot of lecture on understanding

just shows us code an goes over a few things

were basically expected to know stuff that half of which wasnt taught to us in the previous course

paying to self teach so it be like that

[unreal beacon]

okay I came up with something:

#include <iostream>
#include <string>

std::ostream& foo()
{
    return std::cout << "a";
}

int main() {
    foo() << " hello world";
}

there we go

[modest yarrow]

You cannot just create a local ostream object and return a reference to that.
Your compiler will tell you this.

[unreal beacon]

im dead inside now and this is idiotic

well I guess it's tehcnically possible with this.... to comply to the exercise but this is 1000000 levels of cursed

[modest yarrow]

Agreed, this is a BS assignment.

[unreal beacon]

yeah....

ill admit the local ostream was kinda dumb 😅, but I figured it had to be that as that would make some inkling of sense

but never actually tried making one locally, cause well thats dumb

[modest yarrow]

You only involve an ostream if you overload the free function streaming operator, so you could write code like:

for (unsigned int count = 0; count < 10; count++)
  cout << airCanada[count];

This code does not require there to be a Ticket::display() function.

The operator may of course use Ticket::display() instead of being made a friend to the class.
But doing so would required the ostream to be passed - by non-const reference - into said function as a parameter.

[unreal beacon]

yeah exactly and thats the entire thing that made me so so confused

like the only way I can think of to make this work is the above I posted.... and that is just beyond levels of cursed

[modest yarrow]

BS assignment.

The only way to abide by the restrictions placed upon the code as-is, would be to:

std::ostream& Ticket::display() const
{
  // code as before, then...
  return cout;
}

But that's insane.
Why would a function return a reference to a global variable?

This would not survive a peer review in any self respecting company. It smells.

[unreal beacon]

yeah...

it's just weird

a bit of a rant but I loath a lot of uni assigments cause they are non sensical and weirdly arbetrarely restricted

[ruby berry]

was able to figure it out

[ruby berry]

!solved