Contructors and destructors problem

rag84dec · #1 10-Sep-2007, 21:34

Hi,
I the below code i could see 2 constructors and 3 destructors being called....i want to know why....can anyone help me in knowing this???

CPP / C++ / C Code:

class e
{

public:
	e()
		{
				cout<<"Contructor\n";
		}
	~e()
		{
				cout<<"Destructor\n";
		}
	void f(e e1)
		{
				cout<<"In e\n";
		}
};
int main(int argc, char* argv[])
{
	{
	e ee;
	e ee1;
	ee.f(ee1);
	//printf("Hello World!\n");
	//cout<<"Raghava"<<endl;
	}
	int t;
	cin>>t;
	return 0;
}

Kimmo · #2 10-Sep-2007, 23:45

In C++, unlike in some languages, objects are not automatically passed by reference. So the function

CPP / C++ / C Code:

void f(e e1)

is passed a copy of the object, which means the copy constructor is invoked to create the copy.

Since your class doesn't define a copy constructor, you don't get notified of the object's construction. Try adding this to your class:

CPP / C++ / C Code:

e(const e& eCopy )
{
    cout << "Copy constructor\n";
}

Find a book or some online reference about classes, they should tell you about why and when you need a copy a constructor and an assignment operator.

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Contructors and destructors problem

Re: Contructors and destructors problem