c++ - Is it ok to use base class attribute in the initialization list? -

i have class has attribute value depends on attribute base class. base class attribute modified in constructor need value after being modified. tried summarize idea in example:

#include <string> #include <iostream>  class { public:     int att_a;     a(int x) : att_a(x) {         att_a++;     }; // att_a being modified in constructor of };  class b : public { public:     std::string att_b; // att_b different type att_a value obtained att_a     b(int y) : a(y), att_b(std::to_string(att_a)) {}; };  int main(int argc, char const *argv[]) {     b b = b(3);     std::cout << b.att_b << std::endl;     return 0; } 

i'm using attribute att_a class a, modified during it's construction, input function initializes att_b of class b. concerns are:

• is way of accomplishing want?
• even though compiles , run, can cause undefined behavior under circumstances?

• can cause undefined behaviour?

  no.

  when using member initialization list, order defined: first base-classes in order, members in order. @ time create member, base classes , previous declared members instantiated. if switch order in constructor, compiler should output warning.

• is way of accomplishing want?

  since don't tell going classes, can't tell if way, can way if fits needs.