c++ - How can I access the members of objects stored in a vector? -

the code giving problem below. have commented parts give correct output, , not, not know why, , how should accessing class member data normally. read trying access in c style loop isn't great, tried ith iterators met "error: no match 'operator<=' (operand types 'player' , '__gnu_cxx::__normal_iterator >')"

class player { public:     player() {}     player(double strength) {}     virtual ~player() {}     double getstrength() const {         return strength;     }     void setstrength(double val){         strength = val;     }     int getranking() const{         return ranking;     }     void setranking(int val){         ranking = val;     }     int getatppoints() const{         return atppoints;     }     void setatppoints(int val){         atppoints = val;     } protected: private:     double strength; //!< member variable "strength"     int ranking; //!< member variable "ranking"     int atppoints; //!< member variable "atppoints" };  int main() {     vector<player> players(1000);     // player strengths generated normal distribution mean of 5 , standard deviation of 2, values outside range of 0-10 discarded.     generateplayerstrengths(players);      sort(players.begin(), players.end(), sortmethod); // sort descending order      int i=1;     (player : players)     {   // initialise rank of players according strength         a.setranking(i);         i++;         cout << a.getranking() << endl; // returns correctly     }      // returns zeros, random number, more zeros     for(int j=0;j<32;j++) {        cout << players[i].getranking() << endl;     }       cin.ignore(); // keep command window open debugging purposes.     return 0;  } 

for (player : players) 

in order modify objects in vector through a, needs reference.

for (player& : players) 

otherwise, working copies local loop body, , changes not seen when iterate next time.

also, using wrong index variable (i, when should using j) in second loop.