Re: C++ Too many destructors called so few objects

From:

Kai-Uwe Bux <jkherciueh@gmx.net>

Newsgroups:

comp.lang.c++

Date:

Sun, 29 Aug 2010 13:35:54 +0200

Message-ID:

<i5dgmr$nh6$2@hoshi.visyn.net>

Ravi wrote:

Here is the code (also at http://pastebin.com/yw5z2hnG ):

#include <iostream>
#include <vector>
using namespace std;

class X
{
public:
int i;
X();
~X();
};

X::X()
{
i = 1;
cout << "---constructor" << '\n';
}

X::~X()
{
cout << "***desctructor" << '\n';
}

int main()
{
vector<X> *vx = new vector<X>;

Should you have the habit of allocating vectors dynamically, you might want
to reconsider the rationale for that.

cout << "------------------------------------" << endl;
vx->push_back(X());
vx->push_back(X());
vx->push_back(X());
vx->push_back(X());
vx->push_back(X());
cout << "------------------------------------" << endl;
delete vx;
}

I get the output as:

------------------------------------
---constructor
***desctructor
---constructor
***desctructor
***desctructor
---constructor
***desctructor
***desctructor
***desctructor
---constructor
***desctructor
---constructor
***desctructor
***desctructor
***desctructor
***desctructor
***desctructor
------------------------------------
***desctructor
***desctructor
***desctructor
***desctructor
***desctructor

I do not understand why so many destructors are called.

Because so many constructors are called: define the copy constructor and
make it also print messages.

Best

Kai-Uwe Bux