On Jun 29, 11:34am, Vijay <mt.vi...@gmail.com> wrote:
> Hi All,
>
> I am not able to figure out what exactly happening in below code. what
> is control flow. Can anyone clear my confusion?
>
> Code:
> class A
> {
> public:
> A(){cout<<"In Constructor\n";}
> //// A(const A&){cout<<"In Copy Constructor\n";} // if we uncomment
> this, we see different //output .
> ~A(){cout<<"In Destructor\n";}};
>
> try{
> cout<<"In Try\n";
> throw A();
> }
> catch(A &a)
> {
> cout<<"In Catch\n";}
>
> output:
> In Try;
> In Constructor
> In Destructor
> In Catch
> In Destructor
>
> Question 1. I don't know why two times destructor has been called. I
> understand, since i am using reference, so there would not be any new
> object. then why two times destructor got called.
>
> Question 2.
>
> class A
> {
> public:
> A(){cout<<"In Constructor\n";}
> A(const A&){cout<<"In Copy Constructor\n";}
> ~A(){cout<<"In Destructor\n";}};
>
> try{
> cout<<"In Try\n";
> throw A();
> }
> catch(A a)
> {
> cout<<"In Catch\n";}
>
> output:
> In Try;
> In Constructor
> In Copy Constructor
> In Catch
> In Destructor
> In Destructor
>
> Why object created by throw A() has not been deleted while exiting try
> block in above code?
>
> thanks in advance.
>
> Regards,

In the first case, there has to be copy since you are getting two
destructor
calls. The copy is done using the default copy constructor which
doesn't
print any output. Makes sense to me.

I'm not sure why the order of the destructors are different in the
second
example. Could it have anything to do with the fact that the code you
posted for the second example is catching the exception by value? Or
is the missing '&' a typo?