Structs and classes in C++

c_struct.c

#include <stdio.h>

struct Vec2 {
  float x, y;
};

int main() {
  struct Vec2 v;

  v.x = 1;
  v.y = 2;

  printf("%f %f", v.x, v.y);
}

class_class.hpp

class Vec2 {
 public:
  float x, y;

  void add(Vec2 other) {
    x += other.x;
    y += other.y;
  }
};

class Vec3 : public Vec2 {
 public:
  float z;

  void add(Vec3 other) {
    Vec2::add(other);
    z += other.z;
  }
};

class_struct.hpp

class Vec2 {
 public:
  float x, y;

  void add(Vec2 other) {
    x += other.x;
    y += other.y;
  }
};

struct Vec3 : public Vec2 {
  float z;

  void add(Vec3 other) {
    Vec2::add(other);
    z += other.z;
  }
};

main.cpp

#include <iostream>
#include <struct_struct.hpp>
// #include <class_class.hpp>
// #include <class_struct.hpp>
// #include <struct_class.hpp>

int main() {
  Vec3 v1, v2;

  v1.x = 1;
  v1.y = 2;
  v1.z = 3;
  v2.x = 3;
  v2.y = 2;
  v2.z = 1;

  v1.add(v2);

  std::cout << v1.x << " " << v1.y << " " << v1.z << std::endl;
}

struct_access_mod.cpp

#include <iostream>

struct Vec2 {
  float x, y;

  void add(Vec2 other) {
    x += other.x;
    y += other.y;
  }

 private:
  bool inverted;
};

int main(void) {
  Vec2 v;
  std::cout << v.inverted;
}

struct_class.hpp

struct Vec2 {
  float x, y;

  void add(Vec2 other) {
    x += other.x;
    y += other.y;
  }
};

class Vec3 : public Vec2 {
 public:
  float z;

  void add(Vec3 other) {
    Vec2::add(other);
    z += other.z;
  }
};

struct_struct.hpp

struct Vec2 {
  float x, y;

  void add(Vec2 other) {
    x += other.x;
    y += other.y;
  }
};

struct Vec3 : public Vec2 {
  float z;

  void add(Vec3 other) {
    Vec2::add(other);
    z += other.z;
  }
};