Constructor & Destructor

Question

so i was coding the Singleton Design pattern which states that only one object of a class is allowed. i was doing some things and I made user defined constructors and destructors. so what i was doing create object, display it and then destroy it.
but output sequence was:
1.message of constructor
2. message of destructor
3. msg i was printing

What is happening here? Why destructor gets called immediately after calling constructor?

Answer 1

Good Question, A constructor in C++ is called just after the creation of an object of that class . it's basically used for initialising data members of an object
class sample {
int data;
//constructor
sample(){
data=10; // just some value
cout<<"data initialised successfully";
}
//Destructor
~sample(){
cout<<"\nthe object out of scope";
}

void disp(){
cout<<"\n display function called ";
}

};

void main()
{
sample obj; // statement 1
obj.disp(); // statement 2
}

in the above give program
when statement 1 is executed
the object obj is created in memory and the constructor is called
and when the statement 2 is executed the disp() member function of obj is called
and AFTER execution of the statement 2
we can see that object obj is no longer used in program right , then the object obj is said to be out of SCOPE
and By definition a Destructor is executed when an object goes out of its scope

output will be:
data initialised successfully
display function called
the object out of scope

Answer 2

that is supposed to happen. but i am explicitly deleting object by delete operator. thats what causing problem.. i cant figure out how to tackle that situation.

Answer 3

Can you type the code? If you are deleting object with delete it means you are calling its destructor.

Answer 4

delete this; add this statement to any member function of class sample
class sample{

void deleteobj(){
delete this;
}
};

Answer 5

i can do like this. but i really want to destroy object using destructor. and i cant post code as it is huge. i can tell what i am doing.
Create Stack
Push Something
Display
Delete Stack( by delete).
Output is like:

Object Created
Object Deleted
Stack Content Displayed.