Question

The following piece of code gets compiled under g++ 4.6.3 for Linux

#include <iostream>

class A {
  public:  

    int x;
    std::string c;

    A(int x,std::string c):x(10),c("Hi"){
    }

    ~A(){
      std::cout << "Deleting A()" << std::endl;
    }
};

class B : public A {
  public:

    B():A(20,"Hello"){
    }

    ~B(){
      std::cout << "Deleting B()" << std::endl;
    }
};

int main(){
  B o;
  std::cout << o.x << std::endl;
  std::cout << o.c << std::endl;
  return(0);
}

but it does not do what is supposed to do, the type B is not able to change the values of that 2 variables that it inherit from A.

Any explanations about why this doesn’t work properly ?

Answer 1

Your base constructor takes those values…and completely disregards them!

Change this:

A(int x,std::string c):x(10),c("Hi"){}

to this:

A(int x,std::string c):x(x),c(c){}