Linker error in dev c++!! ld returned 1 exit status..

zzzzzzzzz (2)
the error shows:
[Linker error] undefined reference to `vtable for BASIC'
[Linker error] undefined reference to `vtable for BASIC'
ld returned 1 exit status
D:\Dev-Cpp\project\course\Makefile.win [Build Error] [course_des.exe] Error 1

I really don't know what's wrong with it:
here's my code:(3 parts:main.cpp;implement.cpp;headers.hpp)
by the way,anybody could tell me how to use the STL function "sort" in my own class "STU"??Coz' i've left a blank in the function "void sort_by_id()";
main.cpp
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#include <cstdlib>
#include <iostream>
#include <fstream>
#include <string>
#include <vector>

#include "headers.hpp"

using namespace std;
int select_menu(){
    cout<<"************菜单************"
        <<"0.基本信息管理"
        <<"1.课程信息管理"
        <<"2.成绩信息管理"
        <<"3.退出系统"<<endl;
    int choice;
    do
    {cout<<"请选择0~3中的某一个选项:";
    cin>>choice;
    }while(choice<0||choice>3);
    return choice;
}
 
int main()
{
    int choose;
    BASIC_MANAGE obj1;
    /*for(;;){
            choose=select_menu();
            if(choose==0) BASIC_MANAGE *obj1=new BASIC_MANAGE;
            if(choose==1) COURSE_MANAGE *obj2=new COURSE_MANAGE;
            if(choose==2) SCORE_MANAGE *obj3=new SCORE_MANAGE;
            //switch(select_menu()){
            //case 0:break;
            //case 1://break;
            //case 2://break;
            //case 3:exit(0);
            //}
            }*/
    system("PAUSE");
    return 0;
}


implement.cpp:
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#include <fstream>
#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <iomanip>
#include "headers.hpp"
#define COURSE_NUM 4
using namespace std;


bool BASIC::idcomp(STU *i,STU *j){
     return((i->id)<(j->id));}
bool BASIC::namecomp(STU *i,STU *j){
     return((i->name)<(j->name));}
int BASIC::check_password(){
     string p;
     int count=0;
     do{
     cout<<endl<<"Password:";
     cin>>p;
     if(count>0&&count<2) cout<<"Wrong Password!Please check again!";
     else if(count==2) cout<<"You have tried 3 times!Check failed!";
     }while(p!=pass&&count++<=2);
     if(count>=3) return 0;
     else {cout<<"Check Success!";return 1;}
     }
void BASIC::reset_password(){
     string re;
     if(check_password()==1)
     {cout<<endl<<"Please input new password:";
      cin>>re;
      pass=re;
      }
      }

void BASIC::search_by_id(){
     string temp_id;
     int count=0;
     cout<<"Please input id:";
     cin>>temp_id;
     for(vector<STU*>::iterator i=info.begin();i!=info.end();i++)
     {if((*i)->id==temp_id) {index=i;show();count++;}}
     if(count==0) cout<<"Record not found!"<<endl;
     }

void BASIC::search_by_name(){
     string temp_name;
     int count=0;
     cout<<"Please input name:";
     cin>>temp_name;
     for(vector<STU*>::iterator i=info.begin();i!=info.end();i++)
     {if((*i)->id==temp_name) {index=i;show();count++;}}
     if(count==0) cout<<"Record not found!"<<endl;
     }

void BASIC::sort_by_id(){
     //sort(info.begin(),info.end(),idcomp);
     }

void BASIC::sort_by_name(){
     //sort(info.begin(),info.end(),namecomp);
     }

int BASIC_MANAGE::select_menu(){
    cout<<"**********基本信息**********"
        <<"0.从文件读入"
        <<"1.增加一条记录"
        <<"2.按姓名查找"
        <<"3.按学号查找"
        <<"4.按姓名排序"
        <<"5.按学号排序"
        <<"6.修改记录"
        <<"7.删除记录" 
        <<"8.保存到文件"
        <<"9.显示全部记录"
        <<"10.退出" 
        <<endl;
    int choice;
    do
    {cout<<"请选择0~10中的某一个选项:";
    cin>>choice;
    }while(choice<0||choice>10);
    return choice;
}

BASIC_MANAGE::BASIC_MANAGE(){
     int c;
     while(c=select_menu(),c!=10){
     switch(c){
     case 0:read_from_file();break;
     case 1:add_record();break;
     case 2:search_by_name();break;
     case 3:search_by_id();break;
     case 4:sort_by_name();break;
     case 5:sort_by_id();break;
     case 6:search_by_id();modify();break;
     case 7:search_by_id();remove();break;
     case 8:save_to_file();break;
     case 9:show_all();break;
     }
     }
     if(c==10) cout<<"********退出基本信息管理*******"<<endl;
     }

void BASIC_MANAGE::read_from_file(){
     STU *temp=new STU;
     ifstream myfile;
     char url[10];
     cout<<"Please input URL:";
     cin>>url;
     myfile.open(url);
     if(myfile.is_open()){
     while(!myfile.eof()){
     myfile>>temp->name
           >>temp->id
           >>temp->age
           >>temp->sex
           >>temp->major
           >>temp->from;
     info.push_back(temp);
     }
     }
     }

void BASIC_MANAGE::add_record(){
     STU *temp=new STU;
     cout<<endl;
     cout<<" Name:";cin>>temp->name;
     cout<<"   ID:";cin>>temp->id;
     cout<<"  Age:";cin>>temp->age;
     cout<<"Major:";cin>>temp->major;
     cout<<" From:";cin>>temp->from;
     info.push_back(temp);
     }

void BASIC_MANAGE::remove_all(){
     if(check_password()) info.clear();
     }

void BASIC_MANAGE::save_to_file(){
     ofstream myfile;
     char url[10];
     cout<<"Please input URL:";
     cin>>url;
     myfile.open(url);
     if(myfile.is_open()){
     for(vector<STU*>::iterator i=info.begin();i!=info.end();i++)
     {myfile<<(*i)->name<<" "
            <<(*i)->id<<" "
            <<(*i)->age<<" "
            <<(*i)->major<<" "
            <<(*i)->from<<endl;
            }
            }
            }

void BASIC_MANAGE::show(){
     vector<STU*>::iterator rec=index;
     cout<<endl
         <<setw(10)<<(*rec)->name
         <<setw(10)<<(*rec)->id
         <<setw(10)<<(*rec)->age
         <<setw(10)<<(*rec)->major
         <<setw(10)<<(*rec)->from;
         }

void BASIC_MANAGE::show_all(){
     for(vector<STU*>::iterator i=info.begin();i!=info.end();i++)
     show();
     }

void BASIC_MANAGE::modify(){
     vector<STU*>::iterator rec=index;
     cout<<"Modify:"<<endl;
     cout<<" Name:";cin>>(*rec)->name;
     cout<<"   ID:";cin>>(*rec)->id;
     cout<<"  Age:";cin>>(*rec)->age;
     cout<<"Major:";cin>>(*rec)->major;
     cout<<" From:";cin>>(*rec)->from;
     }

void BASIC_MANAGE::remove(){
     vector<STU*>::iterator rec=index;
     char sure;
     cout<<"Remove record.Sure?";
     cin>>sure;
     if(sure=='y'||sure=='Y') info.erase(rec);
     }


headers.hpp:
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#include <fstream>
#include <iostream>
#include <vector>
#include <string>
#include <algorithm>

using namespace std;

class STU{
      protected:
                string name;
                string id;
                int age;
                int sex;
                string major;
                string from;
                string courses[5];
                int score[5];
      friend class BASIC;
      friend class BASIC_MANAGE;
             };

class BASIC{
      protected:
      vector<STU*> info;
      vector<STU*>::iterator index;
      string pass;
      bool idcomp(STU *i,STU *j);
      bool namecomp(STU *i,STU *j);
      public:
             int check_password();
             void reset_password();
             virtual int select_menu()=0;
             virtual void read_from_file()=0;
             virtual void add_record()=0;
             virtual void remove_all()=0;
             virtual void save_to_file()=0;
             virtual void show()=0;
             virtual void show_all();
             virtual void modify()=0;
             virtual void remove()=0;
             void search_by_name();
             void search_by_id();
             void sort_by_id();
             void sort_by_name();
             };

class BASIC_MANAGE:public BASIC{
      public:
             BASIC_MANAGE();
             int select_menu();
             void read_from_file();
             void add_record();
             void remove_all();
             void save_to_file();
             void show();
             void show_all();
             void modify();
             void remove();
             };

thanks for your patience!!
Last edited on
guestgulkan (2942)
So far all i've seen is that you have in the BASIC class a function called virtual void show_all(); which is not pure virtual but you have not defined a function called void BASIC::show_all() in the implementation file.
zzzzzzzzz (2)
Cool!!I've solved it!
Thank you,Master!
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