NOTE:

These are a little sketchy...I'll fill in details 'soon'.

Concatenation

• concatenation:

      String String::operator+(const String & right) const
      {
          char * t = nullptr;
          if ((length > 0) && (right.length > 0))
          {
              t = new char [length+rigth.length+1];
              if (t != nullptr)
              {
                  strcpy(t,string);
                  strcat(t,right.string);
              }
          }
          else if (length > 0)
          {
              t = new char [length+1];
              if (t != nullptr)
              {
                  strcpy(t,string);
              }
          }
          else if (right.length > 0)
          {
              t = new char [right.length+1];
              if (t != nullptr)
              {
                  strcpy(t,right.string);
              }
          }
          // no else since nullptr above covers it...
  
          String t2(t);    // what should t2's translation state and case
                           // sensitivity be?
  
          if (t != nullptr)   // avoid memory leak!
          {
              delete [] t;
              t = nullptr;
          }
          return t2;
      }
  

• concatenation to a Cstring: (cheap but effective)

      String String::operator+(const char right[]) const
      {
          return *this + String(right);
      }
  

• concatenation to a char:

      String String::operator+(const char right) const
      {
          return *this + String(right);
      }
  

Prepend

• there's really no such thing here, but we can concatenate with non-objects on the left:

      String operator+(const char left[], const String & right) // friend?
      {
          return String(left) + right;
      }
  

• and with char:

      String operator+(const char left, const String & right) // friend?
      {
          return String(left) + right;
      }
  

Append

• append String:

      String & String::operator+=(const String & right)
      {
          return *this = *this + right;
      }
  

• append Cstring:

      String & String::operator+=(const char right[])
      {
          return *this = *this + right;
      }
  

• append char:

      String & String::operator+=(const char right)
      {
          return *this = *this + right;
      }