Overloading += operator

[aab1990]

I have string class that I have been working on for a while and I don't know how to attack the += operator. I have completed the + operator with no trouble but the += is really tough.

I am posting my constructor and my + operator...please let me know if anything else would let you help me more.

String::String( const char A[] )
{
   char X = A[0];
   int pos = 0;
   Length = 0;

   while (X!='\0')
   {
      Length++;
      pos++;
      X = A[pos];
   }
   Capacity = 16;
   while (Length > Capacity)
   {
      Capacity+=16;
   }
   Mem = new char[Capacity];
   for (unsigned I=0; I<Length; I++)
   {
      Mem[I] = A[I];
   }
}

String::String( const String & A)
{
   this->Capacity = A.Capacity;
   this->Length = A.Length;

   this->Mem = new char[Capacity];

    for ( unsigned I=0; I<this->Length; I++ )
   {
      this->Mem[I] = A[I];
   }
}

String operator+( const String& A, const String& B )
{
   char X[A.length()+B.length()];

   for( unsigned I=0; I < A.length(); I++ )
   {
      X[I] = A[I];
   }
   for( unsigned J=0; J < A.length()+B.length(); J++ )
   {
      X[J+A.length()] = B[J];
   }
   return String( X );
}

[jsmith]

*this = *this + rhs;