c++ - initializing const fields in the constructor -

const fields in c++ must initialized in initialization list, makes non trivial computation of interdependent values constructor parameters.

what is(are) best way(s) translate, example, piece of java code c++ ?

public class someobject {   private final string some_string;   private final int some_int;    public someobject(final string input_filename){     somereader reader = new somereader(input_filename);      some_string = reader.getstring();     some_int = reader.getint();      reader.close();   } } 

i thought of encapsulating sub-object in someobject, shifting problem; or constructing object using static method:

class someobject {   private:     const std::string some_string;     const int some_int;    public:     static someobject unserialize(const char * input_filename){       somereader reader = new somereader(input_filename);        string str = reader.get_string();       int = reader.get_int();        reader.close();        someobject obj(str, i);       return obj;     };      someobject(const std::string str, const int i) :       some_string(str),       some_int(i)     {}; } 

is there better solution ?

thank you.

this great application c++11 constructor delegation:

class someobject {   private:     const std::string some_string;     const int some_int;    public:     // "real" constructor someobject     someobject(std::string str, const int i) :       some_string{std::move(str)},       some_int{i}     {}      // deserialize somereader (delegates primary constructor)     someobject(somereader& reader) :       someobject{reader.get_string(), reader.get_int()} {}      // deserialize somereader (accepts rvalues,     //   delegates lvalue constructor)     someobject(somereader&& reader) :       someobject{reader} {}      // deserialize named file (delegates somereader&& constructor)     someobject(const char* input_filename) :       someobject{somereader{input_filename}} {} };