C++ vector与dequeue的特性

class CRobotPose2D  : public mrpt::utils::CSerializable
{
    CRobotPose2D() {}
     CRobotPose2D(double x, double y, double phi)
    {
        setX(x);
        setY(y);
        setPhi(phi);
    }
}

//法1
std::vector<CRobotPose2D> func(const std::deque<CRobotPose2D> &in)
{
    std::vector<CRobotPose2D> pose_tab;

    pose_tab.resize(in.size()); //以前有的数据不变.新添加的数据以默认构造函数填充值

    for(size_t i = 0; i < in.size(); ++i)
    {
        pose_tab[i] = in[i]; //operator[] 算法效率极高,仅次于迭代器,极致可以用指针
    }

    return pose_tab;
}


//法2
std::vector<CRobotPose2D> func(const std::deque<CRobotPose2D> &in)
{
    std::vector<CRobotPose2D> pose_tab;

    pose_tab.reserve(in.size()); //提前分配内存大小

    for(auto &v : in)
    {
        pose_tab.push_back(v); //空间足够,不会引起内存重分配, push_back性能低于operator[]
    }

    return pose_tab;
}

//法3:
std::vector<CRobotPose2D> func(const std::deque<CRobotPose2D> &in)
{
    std::vector<CRobotPose2D> pose_tab;

    pose_tab.reserve(in.size()); //提前分配内存大小
    pose_tab.insert(pose_tab.end(), in.begin(), in.end()); //迭代器复制插入.简单高效. 比push_back高效
    return pose_tab;
}
   

std::vector<CRobotPose2D> pose_tab;
CRobotPose2D in;
pose_tab.resize(3);
pose_tab[0] = in;     //operator[]  强烈推荐该方法
pose_tab.a(0) = in;   //at