c++ - How to initialize a vector of a class type in a constructor -

i have class

class effeid { public:   effeid(int a=0,int b=0,int c=0,int d=0):first(a),second(b),third(c),fourh(d){};   int first;  int second;  int third;  int fourh;  }; 

and second class

class axeeffect { public:  //and want initialize constructor in way:  axeeffect(int=0,string="",int=0,int=0,int=0,int=0,vector<effeid>??? ); 

how initialize part vector 0?

to create default argument vector<t> construct one, else.

class foo { public:     foo(const vector<int> &v = vector<int>()) : _v(v) {} private:     vector<int> _v; }; 

also, wouldn't take vector value. take reference avoid unnecessary copy.