Vector array of object pointers

shumi · #1 01-Oct-2008, 18:27

I am facing a problem while executing the below c++ code. Could you please tell me where I have gone wrong. I am very new to c++.

CPP / C++ / C Code:

#include "stdafx.h"
#include "vector"
#include "iostream"

using namespace std;

class abc
{
public:
	int a;
	int *b;
	int c;
public:
	abc();
	~abc();
};
abc::abc()
{
	a=1;
	b=NULL;
	c=3;
}
abc::~abc()
{
	if(b != NULL)
		b =NULL;
}
int _tmain(int argc, _TCHAR* argv[])
{
	vector<abc *> Arr1;
	Arr1.resize(10);

	for(int i=0; i<10; i++)
	{
		abc obj;
		obj.a = i;
		obj.b = (int *)malloc(10*sizeof(int));
		for(int j=0; j<10; j++)
			obj.b[j] = i;
		obj.c = i+1;
		
		Arr1[i] = &obj;
	}

	for(int l=0; l<10; l++)
	{
		cout << Arr1[l]->a << "\t(";
		for(int m=0; m<10; m++)
               {
                        // getting an error at this place
			cout << (Arr1[l]->b)[m] << ", ";  
               }
		cout << ")\t" << Arr1[l]->c << endl;
	}
	cin.get();
	return 0;
}

Could any please correct the error I am facing above.

ocicat · #2 01-Oct-2008, 19:25

Quote:

Originally Posted by shumi

i am facing a problem while executing the below c++ code.

You have many misperceptions about C++:

It is unclear whether this is meant to be a console application or an MFC application. This subforum is for generic platform agnostic programming. Microsoft-specific questions should go in the Microsoft forum.
A standard C++ application requires a main() function. _tmain() is MFC specific.
Standard headers require angle brackets. Header files expected to be found in the current directory are denoted by double quotes. The following:
CPP / C++ / C Code:
#include "vector" #include "iostream"
...should be replaced by:
CPP / C++ / C Code:
#include <vector> #include <iostream>
The class definition for abc has two public sections. I can only assume that you were experimenting with relaxing member access.
The principal problem in your code is that the objects created within the scope of your for-loop (What you are naming obj...) are destroyed at the end of the loop regardless of whether you save a pointer. The question you need to answer to yourself is why create an array of pointers? Why not create an array of objects?
CPP / C++ / C Code:
(Arr1[l]->b)[m]
...is incorrect syntax. If you ultimately want to use an array, you will want to use the following instead:
CPP / C++ / C Code:
Arr1[l]->b[m]

Lastly, when posting code, please place a [cpp] code tag before & [/cpp] aftewards to both preserve formatting & color-code keywords & identifiers.

Peter_APIIT · #3 03-Oct-2008, 04:18

Use smart pointer instead.

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Vector array of object pointers

Re: Vector array of object pointers

Re: Vector array of object pointers