const - Accessor functions in class c++ -

const - Accessor functions in class c++ -

for illustration have accessor function class:

class { public: int a; int& geta() const; }; int& a::geta () const { homecoming a; // error: invalid initialization of reference of type 'int&' look of type 'const // int' }

the questions are: 1. info fellow member 'a' not of type 'const int', why error? 2. when alter homecoming type int works. why?

because specify geta() const. returning non const reference fellow member variable method declared const allow modify value referenced.

if want read-only accessor declare accessor as

const int& a::geta() const

otherwise must remove constness method.

turning returned value int allowed because not returning reference anymore, re-create of a there no way modify original fellow member variable.

mind allowed have them both available:

int& geta() { homecoming a; } const int& geta() const { homecoming a; }

c++ const accessor