c++ - Erase operation on vector not working -


i new c++ , having difficulties getting vector.erase operation work.

i have database class such:

template <class t> class database {     protected:         std::vector<t> m_database;         int m_counter;     public:         database();         virtual ~database();          // accessor methods.         t& getobject(int objectid);         bool exists(int objectid);          // mutator methods.         void add(t object);         void del(int objectid); };

and in practice, using code such:

database<account> accountdatabase;

account base class, 2 derived classes, chequingaccount , savingsaccount.

i inserting accounts, regardless of type (could account, chequingaccount, savingsaccount) database using:

template <class t> void database<t>::add(t object) {     m_database.push_back(object);     ++m_counter; }

however, having issues delete operation. searching corresponding objectid , deleting vector.

// deletes specified object database. template <class t> void database<t>::del(int objectid) {     std::vector<t>& database             = m_database;     typename std::vector<t>::iterator = database.begin();      while (it != database.end()) {         if ((*it).getid() == objectid) {             = database.erase(it);         } else {             ++it;         }     } }

unfortunately delete operation not working @ all. having issues pulling derived class database, being pulled out account type. believe these 2 issues tied noob c++ skills , bad design.

any appreciated! thanks!

edit

by not working, mean object not deleted database. apologize confusion.

the account classes:

class account {     protected:         int m_id;         double m_balance;         std::string m_name, m_type;     public:         account(int id, int userid, double balance = 0, std::string name = ""); // constructor.         ~account(); // destructor.          // accessor methods.         // returns m_id aka objectid         int getid() const; }  class chequingaccount: public account {     public:         chequingaccount(int id, int userid, double balance, std::string name) : account(id, userid, balance, name) {} }  class savingsaccount: public account {     public:         savingsaccount(int id, int userid, double balance, std::string name) : account(id, userid, balance, name) {} }

note remove function far better in terms of std::remove_if:

auto enditerator = std::remove_if(m_database.begin(), m_database.end(),     [=](t const& entry) { return entry.getid() == objectid; }     ); m_database.erase(enditerator, m_database.end());

that said, version not incorrect, inefficient. "doesn't work"? note maintain separate object id in database never put id objects store.


Comments

Post a Comment

Popular posts from this blog

Regex find and replace between <div class="customclass"> and </div> tag -

i cant find anywhere working regex expression find , replace text between div tags so there html want select between <div class="info"> , </div> tag , replace other texts <div class="extrauserinfo"> <p>hello world! sample text</p> <javascript>.......blah blah blah etc etc </div> and replace with my custom text codes <tags> asdasd asdasdasdasdasd</tags> so <div class="extrauserinfo"> custom text codes <tags> asdasd asdasdasdasdasd</tags> </div> here refiddle code there , can see want replace whole bunch of codes between , tag http://refiddle.com/1h6j hope mean :) if there's no nesting, plain match non-greedy (lazy) (?s)<div class="extrauserinfo">.*?</div> .*? matches amount of character (as few possible) meet </div> used s modifier making dot match newlines too. edit : here javas...
Read more

frame rate - JAVA simple fps animation(how can i work with?) -

can me, how can calculate , show fps in animation? want show simple rect (for example). if have code: private final fps = 30; private final size = 10; private int x = 10; private int y = 0; private string myfps; private void start(){ while(true){ moverect(); paint(); } } private void paint(){ g2.drawrect(x, y, size, size); g2.drawstring(myfps, 10, 10); } private void moverect(){ x++; } here copypaste of old simple java graphics+bufferstrategy gameloop test app. animation loop draws few moving rectangles , fps counter. java -cp ./lib/test.jar gameloop2 "fullscreen=false" "fps=60" "vsync=true" //http://www.javagaming.org/index.php/topic,19971.0.html //http://fivedots.coe.psu.ac.th/~ad/jg/ch1/ch1.pdf import java.util.*; import java.awt.color; import java.awt.frame; import java.awt.graphics; import java.awt.graphicsconfiguration; import java.awt.graphicsdevice; import java.awt.graphicsenvironmen...
Read more