c++ - A problem overloading [] in 2 variations -

this generic class:

template<class t, class prnt> class personalvec {  public:     personalvec();     t &operator[](int index) const;     const t &operator[](int index) const;  private:     std::vector<t> _vec;  }; 

i'm required implement 2 versions of [] operator:
1 return const reference , regular 1 return reference. when compile get:
personalvec.hpp:23: error: ‘const t& personalvec<t, prnt>::operator[](int) const’ cannot overloaded
personalvec.hpp:22: error: ‘t& personalvec<t, prnt>::operator[](int) const

i've put either 1 of them remark , compile, guess colliding somehow. problem , how can fix it?

thank you!

return type of function not criteria can used overloading of functions. function can overloaded if:
1. different no of arguments
2. differnt sequence of arguments or
3. different types of arguments

you trying overload function based on return type , hence gives error.
'const' keyword can overload functions if above 3 criterias not met. simple solution can make 1 of function const , keep other normal function