Mine

// test.hclass A {  public:    A() : a(4) {}  private:    int a;};class B : public A {  public:    B(); // in c  private:    int b;};// test.cpp#include "test.h"B::B(){  b = 4;}// main.cpp#include "test.h"int main(){  A a;  B b;}// `g++ test.cpp main.cpp` gibt keine fehler...