UserDefinedTypeConversion.cpp

struct Vector3_A {
    float x;
    float y;
    float z;
 };

class Vector3_B {
    Vector3_B(float x, float y, float x);
    
    float getX();
    float getY();
    float getZ();
    
private:
    float m_coords[3];
};

class MyVectorWrapper : public Vector3_B {
    public:
    explicit MyVectorWrapper(const Vector3_A &inVal)
        : Vector3_B(inVal.x, inVal.y, inVal.z)
        {}
        
    explicit operator Vector3_A() {
        return Vector3_A { getX(), getY(), getZ() };
    }
};

void foo() {
    Vector3_A aVector;
    MyVectorWrapper myVector(aVector);
    // ...
    
    Vector3_B bVector(myVector);
    // ...
}