[SOLVED] Can we access a class attribute by the class name in C++?

Question

I am currently working on something which requires extensive use of string manipulation. So I thought of writing my own library for strings (main aim was to mould the in-built functions of the string class to my needs). So this question arose in my mind that can we access an attribute of a class using the class name itself.

For example, in my class (called String), I have a public member called str (of type std::string). So suppose that a variable of the defined type String is declared. I want

String new_string = name_of_old_string_variable; //operator= is already defined

To be compiled as

String new_string = name_of_old_string_variable.str;

I know that I'm not good with words, so you can check out the code for better understanding of what I want to do.
https://code.sololearn.com/cxqUAE1EJVea/?ref=app

Answer 1

XXX , Something like this?

Edit: I have also overloaded stream insertion operator just to show assignment is working.

https://code.sololearn.com/cTEfKDKXT4Kg/?ref=app

Answer 2

Not sure I understand it, doesn't
std::string old_string = ...;
String new_string = old_string;
already compile correctly? Apart from not returning *this.
( using std:: to make it clear which string it is )

And it does as well if you replace std::string with String and replace the '= ...' with { ... }

Answer 3

I know it doesn't say std::string new_string = old_string.

I was just thinking you meant replacing std::string with String because of the comment.

I'm still not completely sure what you mean because
String old_string{"abcd"};
String new_string = old_string;
already compiles.

You may want to define a String( const char* ) to do
String old_string = "abcd";
though.

Answer 4

I see, then you probably want to define the assignment operator:
String& operator= ( const String& x){
this->str = x.str;
return *this;
}
like in Omkar's example ( don't forget to return String& otherwise chained assignments won't work )
And the constructor equivalent:
String( const String& x )
: str( x.str )
{}
Though you may have to decide what to do with the 'other attributes' here, since they'll be uninitialized.

Answer 5

🇮🇳Omkar🕉 oh damn!! I can't believe I didn't think of that. Thanks for pointing out. Thanks to Dennis too. I just wasted my time. I don't know why instead of thinking over it, I had supposed it was impossible.

Answer 6

Dennis look carefully, it's
string new_string = old_string;

Not
String new_string = old_string;

And to further clarify, I want to be able to do
String = String;
And only change the attribute 'str' of the String on the left hand side.

Just like we do
string = string;

(I'll just add std::string everywhere so that there is no confusion between String and string)

Answer 7

Dennis
String new_string = old_string;

compiles but overrides the rest of the attributes also. See the code now.

(And sorry I'm just bad at explaining)