如何通过不带参数Java的方法返回新对象

Question

I'm a Java beginner and wanted to ask how I can return a new object with a method with no parameters given.

The instructions are the following: «a method division without parameters, allowing the cell to divide; the method division returns a new Cell; the new cell is a copy of the former cell; the copy will then follow a mutation of its color;»

My question is, how do I implement the copy constructor in the method, so if I call Cell.division() that it will take "Cell" as an Object and copy it?

If I write

    public Cellule division(){
    Cell tmpCell = new Cell(object);
   //some mutations I need to code
    return tmpCell;

it says "object" cannot be resolved to a variable

Code of the Cell Class:

private String nom;
private double taille;
private int energie;
private String couleur;

//default
public Cellule(){
    nom = "Pyrobacculum";
    taille = 10;
    energie = 5;
    couleur = "verte";
}

//copy constructor
public Cellule(Cellule autreCellule){

    energie = autreCellule.energie;
    taille = autreCellule.taille;
    nom = autreCellule.nom;
    couleur = autreCellule.couleur;

}

//parameters
public Cellule(String nom, double taille, int energie, String couleur){
    this.taille = taille;
    this.energie = energie;
    this.nom = nom;
    this.couleur = couleur;

}

//return Energy
public int getEnergie(){
    return energie;
}
//return Height
public double getTaille(){
    return taille;
}

//outprint
public void affiche(){
    System.out.println(nom + ", taille = " + taille + " microns, énergie = " 
+ energie + ", couleur = " + couleur );
}

//division method
 public Cellule division(){
    Cell tmpCell = new Cell(object);
   //some mutations I need to code
    return tmpCell;

Thanks a lot

Answer 1

Since you are not passing obeject as parameter and you are not declaring it as local variable its throwing "object" cannot be resolved to a variable error.

So in your case it needs to be declared globally.

class Cell {
    int i;
    Cell c= new Cell(2);

    Cell(Cell clone ) {
        this.i = clone.i;
    }

    Cell(int i ) {
        this.i = i;
    }
    public Cell division(){
        Cell tmpCell = new Cell(c);

        return tmpCell;
    }
}