C/C++ の構造とクラスの違い

#include <iostream>
using namespace std;
class my_class {
   int x = 10;
};
int main() {
   my_class my_ob;
   cout << my_ob.x;
}

This program will not be compiled. It will generate compile time error for
the private data member.

#include <iostream>
using namespace std;
struct my_struct {
   int x = 10;
};
int main() {
   my_struct my_ob;
   cout << my_ob.x;
}

#include <iostream>
using namespace std;
class my_base_class {
   public:
   int x = 10;
};
class my_derived_class : my_base_class {
};
int main() {
   my_derived_class d;
   cout << d.x;
}

This program will not be compiled. It will generate compile time error that the variable x of the base class is inaccessible

#include <iostream>
using namespace std;
class my_base_class {
   public:
   int x = 10;
};
struct my_derived_struct : my_base_class {
};
int main() {
   my_derived_struct d;
   cout << d.x;
}