CS 340 - 2/12/13

Happy Birthday Abe

// Copy Constructor for MyString

MyString::MyString (const MyString& pStr)
   : str_ ( new char [pStr.length_ + 1]),
     length_ ( pStr.length_ )
{
   strcpy ( str_, pStr.str_ );
}

//  Use of assignment operator to produce a
//  deep copy
//    MyString s1, s2, s3;
//      s1 = s2;       // s1.operator= (s2);
//      s1 = s2 = s3;  
        // s1.operator= ( s2.operator= (s3) );
//      s1 = (An Instance of MyString);
//      s1 = s1;

MyString& MyString::operator= (const MyString &rhs) 
{
   // Step 1 - makes sure this is not the same instance
   //            as rhs
   if (this == &rhs)
      return *this;

   // Step 2 - deallocate existing dynamic memory
   // often mimics the destructor code
   delete [] str_;

   // step 3 - set up the copy
   // often mimics the Copy Constructor code
   str_ = new char [ rhs.length_ + 1 ];
   length_ = rhs.length_;
   strcpy (str_ , rhs.str_ );

   // step 4 - return the this pointer by reference
   return *this;
}