C++ Return a Variable of an object - c++

Question

I am learning c++ currently and i have run to this problem:
Error Message: This Code should be of type bool or should be converted to bool.
The main function must stay the same, so i was wondering, that i use the line [A] and actuall return an bool.
The method should compare two cubics with each other, if they are the same or not the same.
Thanks in advance! :) <3
#include <iostream>
#include <cfloat>
class cubics
{
private:
double x,y,z;
bool var;
public:
cubics same(cubics cube)
{
double difference_x = x - cube.x;
double difference_y = y - cube.y;
double difference_z = z - cube.z;
if ( // If the difference between two objects are 0, then both cubics are the same; epsilon is used because we calculate with double floating precision to avoid the error)
(difference_x <= std::numeric_limits<double>::epsilon( )) and
(difference_y <= std::numeric_limits<double>::epsilon( )) and
(difference_z <= std::numeric_limits<double>::epsilon( ))
)
{
return (cube.var= true); // [A] I'm actually returning bool. But does the compiler want me to return the whole object!?
}
else
{
return (cube.var=false); // [A]
}
}
int main(){
cubics q2,q3;
cout << "The Cubics q2 and q3 are ";
if (q2.same(q3)) // <-- This line confuses me, however it must stay formally for my computerproject the same :) I understand that it means q2.same(q3) == true, but i don't know how i can return a boolean. I tryed [A]
cout << "same." << endl;
else
cout << "not same." << endl;
}
}

Answer 1

To return a boolean, you make the function… return a boolean.
Right now, it is trying to return an object of type cubics:
cubics same(cubics cube)
^^^^^^
Instead:
bool same(cubics cube)
^^^^
And return true, or return false, as appropriate.
That's it!
Your bool var doesn't need to exist at all.
I'd also recommend you take cube by reference; there's no need to take it by value, which makes a copy. So:
bool same(const cubics& cube)