Assignment = operator overloading

Please help to complete this execution of an assignment overloading function.

Here is the instruction:

Assignment operator (=) which will copy the source string into the destination string. Note that size of the destination needs to be adjusted to be the same as the source.

Both addition (+) and assignment (=) operators need to be capable of cascaded operations. This means String3 = String1 + String2, or String1 = String2 = String3 should work.

Here is my .cpp file:

MyString& MyString::operator=(const MyString& rhs)
 {
 
         if(this != &rhs)
         {
 
                 delete [] String;
                 String = new char[Size];
 
              for(int i = 0; i < counter+1 ; i++)
             {       
                   String[i] = rhs.String[i];
             }       
 
 
         }
         return *this;
 
 }
 

It is called in the main.cpp file by:

String1=String2=String3;

I feel as though I am missing something.Help!!

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