c++ - Losing data after reading them correct from file -

i have fallowing class of object class data structure use in main combined. adt(abstract data type) linked list. after read file input data , create , object @ print looks fine after print. after push_back() 3-rd int variable initializated 0. example , code:

ex.in:

1 7 31 2 2 2 3 3 3 

now create objects each line, @ print suppose, after push_back():

1 7 0 2 2 0 3 3 0 

class.h:

class rangle { private:     int x, y, l, b; public:     int solution,prec;     rangle(){         x = y = solution = prec = b = l =0;     }      rangle(int i,int j,int k){         x = i;         y = j;         l = k;         solution = 0; prec=0; b=0;     }     friend ostream& operator << (ostream& out, const rangle& ra){         out << ra.x << " " << ra.y << " " << ra.l <<endl;         return out;     }      friend istream& operator >>( istream& is, rangle& ra){         >> ra.x;         >> ra.y;         >> ra.l;         return ;     } }; 

adt.h:

template <class t> class list { private:     struct elem     {         t data;         elem* next;     };      elem* first;      t pop_front(){         if (first!=null)         {             t aux = first->data;             first = first->next;             return aux;         }          t a;         return a;     }      void push_back(t data){         elem *n = new elem;         n->data = data;         n->next = null;         if (first == null)         {             first = n;             return ;         }         elem *current;         for(current=first;current->next != null;current=current->next);         current->next = n;     } 

main.cpp(after call function in main prints object suppose x var(from rangle class) changes 0 in cases.)

void readdata(list <rangle> &l){     rangle r;     ifstream f_in;     f_in.open("ex.in",ios::in);      for(int i=0;i<10;++i){         f_in >> r;         cout << r;         l.push_back(r);     }