Issue passing a reference to another class within a class - c++

Question

I have created the following class which has an object being passed in by reference and is implemented the following way.
Diablo_Serial_4DLib Display(&DisplaySerial);
ZenDisplay ui(Display);
class ZenDisplay
{
public:
ZenDisplay(Diablo_Serial_4DLib &display);
void setup();
private:
Diablo_Serial_4DLib* _display;
};
The constructor is straight forward and works as expected, no problem so far.
// Constructor /////////////////////////////////////////////////////////////////
ZenDisplay::ZenDisplay(Diablo_Serial_4DLib &display)
{
_display = &display;
}
I want to instantiate ZenSpeakerGroup class and pass in the same reference into it's constructor
class ZenSpeakerGroup
{
public:
ZenSpeakerGroup(Diablo_Serial_4DLib &display);
private:
Diablo_Serial_4DLib* _display;
};
ZenSpeakerGroup::ZenSpeakerGroup(Diablo_Serial_4DLib &display)
{
_display = &display;
}
I have modified the original working class to the following
class ZenDisplay
{
public:
ZenDisplay(Diablo_Serial_4DLib &display);
void setup();
private:
Diablo_Serial_4DLib* _display;
ZenSpeakerGroup _speakerGroup;
};
// Constructor /////////////////////////////////////////////////////////////////
ZenDisplay::ZenDisplay(Diablo_Serial_4DLib &display) : _speakerGroup(&display)
{
_display = &display;
}
Now I get the following error and not 100% sure what I am doing wrong.
Arduino: 1.8.16 (Mac OS X), Board: "DOIT ESP32 DEVKIT V1, 80MHz, 921600, None"
/Users/xxx/Documents/Arduino/libraries/ZenOne/ZenDisplay.cpp: In constructor 'ZenDisplay::ZenDisplay(Diablo_Serial_4DLib&)':
/Users/xxx/Documents/Arduino/libraries/ZenOne/ZenDisplay.cpp:14:78: error: no matching function for call to 'ZenSpeakerGroup::ZenSpeakerGroup(Diablo_Serial_4DLib*)'
ZenDisplay::ZenDisplay(Diablo_Serial_4DLib &display) : _speakerGroup(&display)
^
In file included from /Users/xxx/Documents/Arduino/libraries/ZenOne/ZenDisplay.h:14,
from /Users/xxx/Documents/Arduino/libraries/ZenOne/ZenDisplay.cpp:9:
/Users/xxx/Documents/Arduino/libraries/ZenOne/ZenSpeakerGroup.h:18:5: note: candidate: 'ZenSpeakerGroup::ZenSpeakerGroup(Diablo_Serial_4DLib&)'
ZenSpeakerGroup(Diablo_Serial_4DLib &display);
^~~~~~~~~~~~~~~
/Users/xxx/Documents/Arduino/libraries/ZenOne/ZenSpeakerGroup.h:18:5: note: no known conversion for argument 1 from 'Diablo_Serial_4DLib*' to 'Diablo_Serial_4DLib&'
/Users/xxx/Documents/Arduino/libraries/ZenOne/ZenSpeakerGroup.h:15:7: note: candidate: 'constexpr ZenSpeakerGroup::ZenSpeakerGroup(const ZenSpeakerGroup&)'
class ZenSpeakerGroup
^~~~~~~~~~~~~~~
/Users/xxx/Documents/Arduino/libraries/ZenOne/ZenSpeakerGroup.h:15:7: note: no known conversion for argument 1 from 'Diablo_Serial_4DLib*' to 'const ZenSpeakerGroup&'
/Users/xxx/Documents/Arduino/libraries/ZenOne/ZenSpeakerGroup.h:15:7: note: candidate: 'constexpr ZenSpeakerGroup::ZenSpeakerGroup(ZenSpeakerGroup&&)'
/Users/xxx/Documents/Arduino/libraries/ZenOne/ZenSpeakerGroup.h:15:7: note: no known conversion for argument 1 from 'Diablo_Serial_4DLib*' to 'ZenSpeakerGroup&&'
exit status 1
Error compiling for board DOIT ESP32 DEVKIT V1.
This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.
I also tried the following with no success.
_speakerGroup = new ZenSpeakerGroup(&display)
I would appreciate some help on this.

Answer 1

This is the correct way of passing the display reference to ZenSpeakerGroup
ZenDisplay::ZenDisplay(Diablo_Serial_4DLib &display) : _speakerGroup(display)
{
_display = &display;
}

Answer 2

I have made this mistake aswell it's a typo
make sure when you want to intialize a reference define it as a refference
class ZenDisplay{
public:
ZenDisplay(Diablo_Serial_4DLib &display);
void setup();
private:
Diablo_Serial_4DLib& _display; // <--make sure this is a refference
};
now initialize the refference
ZenDisplay::ZenDisplay(Diablo_Serial_4DLib &display){
_display = display;
}