C++ inherit class shows no default constructor - c++

Question

I'm creating a few classes and I decided to create a basic class that other classes will just inherit that basic class
So here is my basic class header
#pragma once
#include "ImageService.h"
class State
{
public:
State( ImageService& is );
~State();
void Update();
};
don't worry about the methods, they aren't the problem.
So now I go ahead and create a IntroState like so (header file)
#pragma once
#include "State.h"
class IntroState : public State
{
public:
IntroState(ImageService& imageService);
~IntroState();
GameState objectState;
};
and here is the cpp file
#include "IntroState.h"
IntroState::IntroState(ImageService& imageService)
{
//error here
}
IntroState::~IntroState()
{
}
at the constructor it is stating "no default constructor for class "State"", now what I think is going on is, the default constructor for State needs a imageService reference passed to it. So how would I pass the imageservice in this constructor to the state constructor?

Answer 1

Your base class has no default constructor, which is what gets implicitly called in your current derived class constructor. You need to explicitly call the base's constructor:
IntroState::IntroState(ImageService& imageService) : State(imageService)
{
}

Answer 2

The usual way:
IntroState::IntroState(ImageService& imageService)
: State(imageService)
{
}

Answer 3

You should call the constructor of State too, like this:
IntroState::IntroState(ImageService& imageService)
: State(imageService) {
}
Tip: Don't use:
#pragma once, use guards!
Example:
#ifndef GRANDFATHER_H
#define GRANDFATHER_H
class A {
int member;
};
#endif /* GRANDFATHER_H */
You can read more about the include guards in wikipedia.
You see #pragma is not standard. Neither became in C++11 (link).