How to use a vector within a class - c++

Question

I used the Fireworks init function to store a particle into the particles vector class.
And when I try to retrieve the count of the particles vector in the update() function, the particles vector is empty. Why?
Fireworks.cpp class:
void Fireworks::init(){
float x = randf();
float y = - 1 * randf(); //Going UP
float z = randf();
Particle part(position,Vector3f(x,y,z), color, randInt(1,50));
particles.push_back(part);
}
bool Fireworks::update(){
Particle particle;
int count = particles.size(); //Total num of particles in system
cout << particles.size() << " ";
}
class Fireworks: public ParticleSystem {
private:
void init();
public:
Fireworks(Vector3f pos, Vector3f col) {
position = pos;
color = col;
init();
}
virtual bool update();
};
particlesystem.h
class ParticleSystem {
protected:
vector<Particle> particles;
public:
//virtual Particle generateParticle();
virtual bool update(){return false;};
};
main.cpp
ParticleSystem *PS;
int main( int argc, char *argv[] ) {
PS = &Fireworks(Vector3f(0,0,0), Vector3f(200,0,255));
glutIdleFunc(move);
}
void move()
{
PS->update();
}

Answer 1

PS = &Fireworks(Vector3f(0,0,0), Vector3f(200,0,255));
This introduces undefined behavior. The right hand side creates a temporary, which will be deleted as soon as that full expression is over (i.e. right after the ;). PS will point to a deleted object after that line - doing anything with it is undefined behavior.
Use new.
PS = new Fireworks(Vector3f(0,0,0), Vector3f(200,0,255));
Also, you must return from all functions that are declared as returning something (non-void). It doesn't matter if they're virtual or not.