Finishing Touches on Collision Detection

[Labdabeta]

I have the following collision detection function that checks the collision between the line defined by lstart -> lend and the triangle defined by points a,b and c with a normal of nvec. I want to know if it will work and what to put into the missing part. (it is near the start and is commented). Here is my code:

bool Collides(glCoordFloat lstart,glCoordFloat lend,glCoordFloat a,glCoordFloat b,glCoordFloat c,glCoordFloat nvec)
{
    //calculate the dot product of vec and nvec
    double vn=((lend.x-lstart.x)*nvec.x)+((lend.y-lstart.y)*nvec.y)+((lend.z-lstart.z)*nvec.z);
    if (closeEnough(vn,0))//if this is zero than the line is parallel to the triangle!
    {
        //calculate the dot product of start->a point on the plane of the triangle and nvec
        double dn=((lstart.x-a.x)*nvec.x)+((lstart.y-a.y)*nvec.y)+((lstart.z-a.z)*nvec.z);
        if (closeEnough(dn,0))//it IS in the plane of the triangle!
        {
            //check for intersection of the three lines bounding the triangle and the vector
            //I am stuck...
            return ( )
        }
        else
        {
            //there is absolutely no way that that there is an intersection! GOOD BYE!
            return false;
        }
    }
    //ok, so it has a specific point of intersection with the plane, lets find it
    double s;//s is how far along the vector the intersection is!
    s=((nvec.x*(a.x-lstart.x))+(nvec.y*(a.y-lstart.y))+(nvec.z*(a.z-lstart.z)))/vn;
    if (s<0.0||s>1.0)
    {
        //not in the plane, not in the triangle!
        return false;
    }
    glCoordFloat i;//this is the intersection!
    i.x=lstart.x+vec.x*s;
    i.y=lstart.y+vec.y*s;
    y.z=lstart.z+vec.z*s;
    //now to check if i is in the triangle a,b,c
    //calculate the dot-products:
    double uu=((b.x-a.x)*(b.x-a.x))+((b.y-a.y)*(b.y-a.y))+((b.z-a.z)*(b.z-a.z));
    double vv=((c.x-a.x)*(c.x-a.x))+((c.y-a.y)*(c.y-a.y))+((c.z-a.z)*(c.z-a.z));
    double uv=((b.x-a.x)*(c.x-a.x))+((b.y-a.y)*(c.y-a.y))+((b.z-a.z)*(c.z-a.z));
    double uw=((b.x-a.x)*(i.x-a.x))+((b.y-a.y)*(i.y-a.y))+((b.z-a.z)*(i.z-a.z));
    double vw=((c.x-a.x)*(i.x-a.x))+((c.y-a.y)*(i.y-a.y))+((c.z-a.z)*(i.z-a.z));
    double denom=(uv*uv)-(uu*vv);
    s=((uv*vw)-(vv*uw))/denom;//why re-allocate s?
    if (s<0.0||s>1.0)
    {
        //not in the triangle, sorry :C
        return false;
    }
    double t=((uv*uw)-(uu*vw))/denom;
    return (!(t<0.0||(s+t)>1.0));
}