我按书上的套路写的程序，一遇到放进模版类中就糊涂了。请高手帮我看看程序。
#include<iostream>
using namespace std;
template<typename T>
class Vec3
{
private:
    T x;
    T y;
    T z;
    T length;
    T* size;
public:
    T GetX(){return x;}
    T GetY(){return y;}
    T GetZ(){return z;}
    Vec3(T a,T b,T c):x(a),y(b),z(c){}
    Vec3(){}
    Vec3(T i){length=i;size=new T[length];}
    ~Vec3(){delete size;}
    T GetLength(){return length;}
    T& operator[](T i)
    {   
        static T ch;
        if(i>=0&&i<length)
            
        return size[i];
        
        
        else
        {
            cout<<"超出范围。";
            return ch;

        }
    }
   const T& operator[](T i) const
    {
        if(i>=0&&i<length)
            
        return size[i];
        
        else
        {
            cout<<"超出范围。"
            return size[length]-1;

        }
    }
      //流输出
    //友可访问私有成员
    friend ostream& operator<<(ostream& out,Vec3<T>& r)
    {
        out<<"("<<r.GetX()<<","<<r.GetY()<<","<<r.GetZ()<<")";
        return out;
    }   
};
int main()
{
    Vec3<double>a(1,2,3);
    Vec3<int>e(3);
    for(int i=0;i<=2;)
    cout<<(e[1]=a[1])<<endl;
    

    return 0;
}