What is a reference? Isn't it just a pointer?

• Yes and no.
• This is from page 58 of your book.
• A reference is a new type added to c++.
  • On initialization it copies the address
  • After that, it automatically dereferences the address.
• This seems strange, because we have only used references as paramteres.
• But we can declare things to be of a reference type.
• At that level, you see it as a nickname.
• See ref.cpp.
• We have seen returning a reference

  • ostream & operator << (ostream & s, T o) {
         s << f(o);
         return s
    }

  • Note there is nothing special to return a reference.
  • The compiler will do the work.
• We must be careful, however, to return a reference to a persistant object.
• What is wrong with this code?

• int &  Foo(int x) {
     int y {x};
     return y
  }
      

• He discusses pass by value, reference and const reference
  • For changable objects us pass by reference.
  • For non-changable objects preferer pass by const reference to pass by reference.