Updating time and position using GetTickCount() in C++ - c++

Question

Problem: I am attempting to update time using getTickCount without avail.
Situation: I currently obtain the timedifference using getTickCount and pass it into world update method parameters. However within the update method where I update the position, a large value is passed in (even though I have divided by 1000) and so the position adds an odd 4000 to the position vector.
Code below:
Simulation.CPP:
int Simulation::simControlLogic(HWND hWnd, keyEvent event)
{
/* TO DO: add relevant code */
if (event != QUIT)
{
previousTime = 0;
frameStartTime = GetTickCount();
if (previousTime == 0)
previousTime = frameStartTime;
timeDifference = (frameStartTime - previousTime) / 1000.0f; // this generates the difference between the last and current time
world.update(event, &graphics, timeDifference); // update parameters of virtual world
gameLoopDelay(frameStartTime);
simDisplayFrame(hWnd); // display frame
previousTime = frameStartTime; //the current time is set to the previous time for the next loop step
}
return 1;
}
looking into the world Update method:
int WorldData::update(keyEvent kEvent, GraphicsM * pGraphicsModule, float timeStep)
{
//updates the particle
for (int i = 0; i < 3; i++)
{
particles[i].Update(kEvent, pGraphicsModule, timeStep);
}
return 1;
}
looking into particles Update method:
void ParticleModel::Update(keyEvent kEvent, GraphicsM * pGraphicsModule, float timeStep)
{
move(timeStep);
}
looking into move method:
void ParticleModel::move(float timeStep)
{
velocity.y = 0.5F;
velocity.x = 0.5F;
acceleration.x = 0.0F;
acceleration.y = 0.0F;
pos.x += velocity.x * timeStep; //here is the problem. I get a large value e.g 79637.1788 causing pos.x to be ridiculously large
pos.y += velocity.y * timeStep; //here is the problem. I get a large value e.g 79637.1788 causing pos.y to be ridiculously large
}

Answer 1

After moving previousTime to the simulator constructor initializing it to 0, it worked. Thanks for replies