#include <iostream>
#include <stdio.h>

struct Base {
  int v1;
  //    private:   //error!
  int v3;

public: // 显示声明public
  int v2;
  void print() { printf("%s\n", "hello world"); };
};

int main() {
  struct Base base1; // ok
  Base base2;        // ok
  Base base;
  base.v1 = 1;
  base.v3 = 2;
  base.print();
  printf("%d\n", base.v1);
  printf("%d\n", base.v3);
  return 0;
}