CODEWITHSUNDEEP
c++
user1128353
user1128353

Reputation: 3

C++ dynamically increase array size for object-array?

I'm making a game with cocos2d-x. The different objects in the game i want to store in a class (I dont know if this is a good idea, but so i can give every object a lot of attributes). Then i make an array out of the objects and for that i need an own datastructure, where i can push and pop my objects. I tried to write this datastructure, but i think i doing wrong with my push function (i want to dynamically increase array size), especially the delete []? Doesn't that destroy my object-pointers stored?

ObjectArray.h:

#pragma once

#include "C:\Cocos\Projects\FirstGame\proj.win32\anObject.h"

class ObjectArrayList
{
public:
    ObjectArrayList(int c);
    ObjectArrayList();
    virtual ~ObjectArrayList(void);

    void push(anObject *obj);
    void pop(int id);
    int findIndex(int id);
    int getSize();
    int getCapacity();

private:
    int capacity;
    int size;
    anObject **objectList;
};

ObjectArray.cpp:

#include "ObjectArrayList.h"
#include <iostream>
using namespace std;

objectArrayList::ObjectArrayList(int c)
{
    size=0;
    capacity = c;
    objectList = new anObject*[capacity];
}

ObjectArrayList::ObjectArrayList() {
}


ObjectArrayList::~ObjectArrayList(void) {
}

void ObjectArrayList::push(anObject *obj) {

    if(size < capacity) { 

    } else {
        int newCap = 2*capacity;
        anObject **tmpObjectList = new anObject*[newCap];
        for(int i = 0;i<capacity;i++) {
            tmpObjectList[i] = objectList[i];
        }
        delete [] objectList;
        objectList = tmpObjectList;
        capacity = newCap;
    }

    objectList[size] = obj;
    size++;
}

void ObjectArrayList::pop(int id) { //not finish yet
    if(size != 0) {
        size--;
    }
}

int ObjectArrayList::findIndex(int id) {
    return id; 
}

int ObjectArrayList::getSize() {
    return size;
}

int ObjectArrayList::getCapacity() {
    return capacity;
}

anObject.h:

#pragma once

#include "cocos2d.h"

class anObject
{
public:
    anObject(int hp_init, int x, int y);
    anObject();
    virtual ~anObject(void);

    void decreaseHp();
    int getHp();
    void setMyPosition(int x, int y);
    cocos2d::Sprite *getMySprite();


private:
    cocos2d::Sprite *mySprite;
    int hp;
    int midX;
    int midY;
    int isX;
    int isY;
};

Bert

Upvotes: 0

Views: 1061

Answers (2)

Alexis R Devitre
Alexis R Devitre

Reputation: 298

As the comments pointed out... you should save some time and energy and try to use the Standard Template Library (STL).

If you insist on fixing this code, I think you should try referencing objectlist after the delete to see if it's still there... maybe this assignment...

objectList = tmpObjectList;

...is not tolerated.

Instead... try to build a copy constructor "public Object(Object copiedObject){}", make a new Object*[] of the 2X size, populate it, then get rid of the old and... without deleting objectList assign your new Object*[] to it...

The rest seems fine to me... hope this helps.

Upvotes: 1

Code-Apprentice
Code-Apprentice

Reputation: 83527

delete [] objectList;

This only frees the array which objectList points to. It does not free any of the objects in that array.

Upvotes: 0

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