Define operator+ and operator+= for the simple 3D vector class below

Vector3.cpp

// https://repl.it/LO2b

#include <iostream>
using namespace std;

struct Vector3 {
  float x, y, z;
  
  Vector3& operator+(const Vector3& rhs) {
    *this += rhs;
    
    return *this;
  }
  
  // https://cboard.cprogramming.com/cplusplus-programming/33500-operators-3d-vector-mathematics.html
  Vector3& operator+=(const Vector3& rhs) {
    x += rhs.x;
    y += rhs.y;
    z += rhs.z;
    
    return *this;
  }
};

int main()
{
  Vector3 vector1, vector2, resultVector;
  
  vector1.x = 10;
  vector1.y = 20;
  vector1.z = 30;
  vector2.x = 100;
  vector2.y = 200;
  vector2.z = 300;

  resultVector = vector1 + vector2;
  
  cout << "For +, " << "\n";
  cout << "resultVector x: " << resultVector.x << "\n";
  cout << "resultVector y: " << resultVector.y << "\n";
  cout << "resultVector z: " << resultVector.z << "\n";
  
  vector1.x = 10;
  vector1.y = 20;
  vector1.z = 30;
  vector2.x = 100;
  vector2.y = 200;
  vector2.z = 300;
  
  resultVector = vector1 += vector2;
  
  cout << "For +=, " << "\n";
  cout << "resultVector x: " << resultVector.x << "\n";
  cout << "resultVector y: " << resultVector.y << "\n";
  cout << "resultVector z: " << resultVector.z << "\n";
  
  return 0;
}