stackoverflow.com-questions-46921632.cpp

/*
   This code is untest but provided as an example
*/

#include "stackoverflow.com-questions-46921632.h"

void function()
{
    vector3D a();
    vector3D b(3.0f);
    vector3D c(3.0f, 4.0f, 5.0f);
}

int main() {
    function();
    return 0;
}

stackoverflow.com-questions-46921632.h

/*
   This code is untest but provided as an example
*/

class vector3D
{
private:
    float x, y, z;
  
public:
    vector3D() : x(0.0f), y(0.0f), z(0.0f) { };
    vector3D(const float& c) : x(c), y(c), z(c) { };
    vector3D(const float& cx, const float& cy, const float& cz)  : x(cx), y(yc), z(cz) { };
    vector3D(const vector3D& v) : x(v.x), y(v.y), z(v.z) { };
};