C++ Question on Data Abstraction

[madhuti]

Hello can anyone explain about :
The diffrence between Data Abstraction and Encapsulation?
Diffrence between default Copy Constructor and default Assignment Operator Overloading in a Class?

Thanks in Advance

[meton_magis]

I don't know the theory behind c++, just how to use it, but I'd suggest you read

Abstraction (computer science) - Wikipedia, the free encyclopedia
and
Encapsulation (computer science) - Wikipedia, the free encyclopedia

I don't know the second question's topics well enough to coment.

[cgrebeld]

Basically a copy constructor is invoked when creating an instance based on an existing instance. Assignment involves two constructed instances.

MyClass c1;
MyClass c2(c1); <- invokes copy constructor
MyClass c3 = c1; <- also copy constructor

c2 = c1; <- invokes assignment operator

[narayana21g]

Encapsulation is nothing but presenting essentials and hiding the implementation because in traditional prog lang like C there was no security for GLOBAL variables suppose if we declare i=10 , it 'll be accessed by any function that may be relevant or irrelevant so that to safeguard data we need encapsulation in c++
about second thing u can see in "cgrebeld" article he gave the ans

[Rubberman]

Overloading of default copy ctor and assignment operator.

The C++ compiler will create one of each of these automatically for any class that does not have its own. The default copy constructor will do a member-wise copy of components, doing a bit-copy of those that do not have their own copy constructor, such as scalar values, and will initialize those that do with the copied object's component. The default assignment operator will also do a member-wise copy of components, doing a bit-copy of those that do not have an assignment operator, such as scalar values, and invoke the assignment operator for those that do. This is not always what you want to happen in either case and it is STRONGLY recommended that you always implement a copy constructor and assignment operator for every class.