java calling method in other class doesn't recognize changed variables

Question

I am working on developing a simple text-based RPG game. Currently I am working on a system to save the player's progress to a text file that can be reopened and loaded from. This is where I encountered my problem. When calling a getter that returns the value of a single variable in a class, the getter returns the default value of 0 that I have set and doesn't recognize that I changed the value of it throughout the game.

Character Class

public class Character
{
    private int _strength = 0; //initialize the strength variable

    public Character() //constructor
    {  }

    public void setStrength(int strength)  //sets the value of strength
    { _strength = strength; }

    public int getStrength() //gets the value of strength
    { return _strength; }
}

If I create a Character variable in the main game and assign strength a value with the code:

public static void main(String[] args)
{
    Character character = new Character(); //initializes the Character variable

    character.setStrength(5); //sets the character's strength to 5
    System.out.println(character.getStrength()); //prints out 5 as expected.
}

If I go to a different class without the main function in it, such as:

public class SaveSystem
{
    private Character character = new Character(); //exactly the same as above...

    public SaveSystem()
    {  }

    public void saveGame()
    {
        //just to test the methods used earlier
        System.out.println(character.getStrength()));
    }
}

I should be able to go back to that class with the main function and say:

public static void main(String[] args)
{
    Character character = new Character(); //initializes the Character variable
    SaveSystem save = new SaveSystem();

    character.setStrength(5); //sets the character's strength to 5
    save.saveGame(); //containing nothing but the character.getStrength() method
}

and have it print the same value of 5. However, it prints out the value of 0 that is assigned when the strength variable is initialized in the character class. If I change the default value of strength in the character class as shown:

public class Character
{ private int _strength = 5; //initialize the strength variable }

then the save.saveGame method in the main class will print out 5. I have been stuck on this for a few days now, and Google has not been helpful in the slightest despite my efforts.

Both of you are correct. I'm not sure which one to accept as correct on here, though. Thank you so much for your help! I've been stuck for a while on this! — dragonfyyre
– dragonfyyre, Commented Oct 25, 2016 at 16:28

BlackHatSamurai · Accepted Answer · 2016-10-25 16:11:30Z

1

Your issue is that you are creating a new character when you create your save object, rather than passing in the character to save. You might try something like this:

public class SaveSystem
{
    public SaveSystem()
    {  }

    public void saveGame(Character character)
    {
        //just to test the methods used earlier
        System.out.println(character.getStrength()));
    }
}

Then you'd call it like:

public static void main(String[] args)
{
    Character character = new Character(); //initializes the Character variable
    SaveSystem save = new SaveSystem();

    character.setStrength(5); //sets the character's strength to 5
    save.saveGame(character); //containing nothing but the character.getStrength() method
}

answered Oct 25, 2016 at 16:11

BlackHatSamurai

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Comments

Arnaud · Accepted Answer · 2016-10-25 16:11:41Z

1

Your SaveSystem is supposed to save the existing Character objects, not to create brand new ones by itself and save them.

So remove the creation in SaveSystem, and pass your Character to the save method.

public class SaveSystem
{


    public SaveSystem()
    {  }

    public void saveGame(Character character)
    {
        //just to test the methods used earlier
        System.out.println(character.getStrength()));
    }
}

And

public static void main(String[] args)
{
    Character character = new Character(); //initializes the Character variable
    SaveSystem save = new SaveSystem();

    character.setStrength(5); //sets the character's strength to 5
    save.saveGame(character); 
}

answered Oct 25, 2016 at 16:11

Arnaud

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