glDrawArrays doesn't draw - c++

Question

I use vectors to store vertex and normal data
vector<float> vertex;
vector<float> normal;
For example:
normal.push_back(-1);
normal.push_back(0);
normal.push_back(0);
vertex.push_back(BARRIER_RADIUS);
vertex.push_back(POLE_HEIGHT);
vertex.push_back(-POLE_RADIUS);
for (int i = POLE_POINTS, i >= 0; i--)
{
//add more vertex
}
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_NORMAL_ARRAY);
glVertexPointer(3, GL_FLOAT, 0, &vertex[0]);
glNormalPointer(GL_FLOAT, 0, &normal[0]);
glDrawArrays(GL_TRIANGLE_FAN, 0, vertex.size());
glDisableClientState(GL_NORMAL_ARRAY);
glDisableClientState(GL_VERTEX_ARRAY);
//Add some more + Draw some thing else the same way
What I've got from this is nothing. it doesn't draw anything onto the screen.
The previous version, which works, is as follow:
glNormal3f(-1, 0, 0);
glBegin(GL_TRIANGLE_FAN);
glVertex3f(BARRIER_RADIUS, POLE_HEIGHT, -POLE_RADIUS);
for ()
{
//add more vertex
glVertex3f(........);
}
glEnd();
//draw more the same way
Point me to where I've gone wrong.

Answer 1

You have defined vertex as a vector of float, but a geometric vertex consists of 3 floats, so that's a recipe for confusion. The number of vertices is not vertex.size(), but rather one third of that. I'm not sure if that's your only problem, but it's a problem.
You should have the same number of normals as vertices.