Making new Class Instance and adding to linked list

[CodeNoob117]

I have a .cpp file which contains 5 smaller defined classes. In my missile class I have a default constructor and a constructor that I invoke

class Missile{
private:
 
    bool isHuman;
    int xPos = 0;
    int yPos = 0;
 
public:
    Missile(){
 
    }
 
    Missile(int x, int y, bool isPlayer){
        xPos = x;
        yPos = y;
        isHuman = isPlayer;
    }
//Other Methods not shown
 

In my player class, I want to create a new Missile object whenever the player presses the "fire" button.
The method to create the new object is below:

    void fire(){
        Missile *missile = new Missile(xPos, yPos, true);
        (*missile).setShotXPos(xPos);
        missiles.add(missile);
 
        for (int i = 0; i < missiles.getSize(); i++){
            cout << "Player XPos:" << xPos << endl;
            cout << "Missile " << i << " XPos: " << (*missiles.get(0)).getMissileXPos() << endl;
        }
        missile = nullptr;
    }
 

My issue is when creating and adding the pointer object; it doesn't seem to create a new instance of the class-the Missile objects all share the same xPos value which is always the first xPos when the "fire" command is given. The "Missile *missile = new Missile(xPos, yPos, true);" line does not seem to create a new instance of the object with different variables but instead creates a new object with the same variables. Any reason as to why?
Is it necessary for me to always make a separate .cpp and .h file for any class I want to create multiple instances of or can I keep the smaller classes in the same file and still create a new separate instance of the class?
Thanks,
CodeNoob117

[Banfa]

I think your error may be at lines 5 and 6. It is only valid to provide an initialiser like this for static const members.

In fact the code you have posted does not compile for me for this reason

5: error: ISO C++ forbids initialization of member 'xPos'
5: error: making 'xPos' static
5: error: ISO C++ forbids in-class initialization of non-const static member 'xPos'
6: error: ISO C++ forbids initialization of member 'yPos'
6: error: making 'yPos' static
6: error: ISO C++ forbids in-class initialization of non-const static member 'yPos'

[weaknessforcats]

The error is here:

    void fire(){
         Missile *missile = new Missile(xPos, yPos, true);
         (*missile).setShotXPos(xPos);
etc...

In the call to setShotXPos, the xPos argument is the value in the this object and not the one pointed at by missile.


The constructor of Missile has already set xPos. Therefore, xPos for the new Missile is already set.

You need to remove this call.

[CodeNoob117]

Thanks for the ideas! Though, when I did further debugging, I discovered the real problem; the issue wasn't creating new Missile objects- it was in the beginning of the fire() method:

 
Missile *missile = new Missile(xPos, yPos, true);//Something went wrong here
(*missile).setShotXPos(xPos);
missiles.add(missile); //here
missile = nullptr; //and here
 

Originally, I had used a linked list of pointers to point to the new Missiles that were being created and for some reason, the program kept adding the same pointer - it never changed where it pointed to but was making new Missiles that were not being used. I fixed the bug by making a linked list of Missile objects, and then deleting the pointer itself after adding its object to the list-instead of setting it to nullptr.

Missile *missile = new Missile(xPos, yPos, true);
missiles.add((*missile));
delete missile;