#include <iostream>
#include <string>
#include <conio.h>
#include <functional>

using namespace std;

//

class Persoana {
public:
    int varsta;
    string nume, prenume;
    //constructor vid cu scopu pentru declararea vectorului
    Persoana() {}
    Persoana(string nume, string prenume, int age)
    {
        this->nume = nume;
        this->prenume = prenume;
        varsta = age;
    }
    virtual void afisare()
    {
        cout << "\n";
        cout << "Numele: " << nume << "\n";
        cout << "Prenumele: " << prenume << "\n";
        cout << "Varsta: " << Persoana::varsta << "\n";
    }
    string returnName()
    {
        return nume;
    }

    ~Persoana() {};

};

class Angajat :public Persoana {
public:
    string departament;
    int salariu;
    Angajat() {}
    Angajat(string nume, string prenume, int varsta, string departament, int salariu)
        :Persoana(nume, prenume, varsta)
    {
        this->departament = departament;
        this->salariu = salariu;
    }
    virtual void afisare()
    {
        Persoana::afisare();
        cout << "Departament: " << departament << endl;
        cout << "Salariu: " << salariu << endl;
    }
    //Mai jos este sunt 3 "gathers" , care returneaza nume, prenume, varsta
    string returnNume() {
        return nume;
    }

    string returnPrenume() {
        return prenume;
    }

    int returnVarsta()
    {
        return varsta;
    }

};

class Student : public Persoana {
public:
    string tip;
    int an;
    Student() {}
    Student(string nume, string prenume, int varsta, string tip, int an)
        :Persoana(nume, prenume, varsta)
    {
        this->tip = tip;
        this->an = an;
    }

    string returnNume()
    {
        return nume;
    }

    string returnPrenume()
    {
        return prenume;
    }
    int returnAge()
    {
        return varsta;
    }

    virtual void afisare() {
        Persoana::afisare();
        cout << "Tip:" << tip << endl;
        cout << "Varsta:" << varsta << endl;
    }
    
};

void menu()
{
    string n, p, d;
    int i_2=0,v, s, i=0, ok = 0, ok2 = 0, nr=0 , opt, nr2 = 0,nr3=0;
    string num, num2;
    Student student[40];
    Angajat angajat[40];
    Persoana * persoane[80];
    int choice;
    do
    {
        cout << "0.Adaugare student" << endl;
        cout << "1.Adaugare angajat" << endl;
        cout << "2. Cautare" << endl;
        cout << "3. Stergere" << endl;
        cout << "4. Exit" << endl;
        cin >> choice;
        switch (choice)
        {
        case 0:
            
            nr  ;
            cout << "Dati numele: ";
            cin >> n;
            cout << "Dati prenumele: ";
            cin >> p;
            cout << "Dati varsta: ";
            cin >> v;
            cout << "Dati tip: ";
            cin >> d;
            cout << "Dati an:";
            cin >> s;   
            student[nr2] = Student(n, p, v, d, s);
            persoane[i] = &student[nr2];
            nr2 = nr2   1;
            i = i   1;
                for (i = 0; i < nr; i  )
                {
                    persoane[i]->afisare();
                }
            break;
        case 1:
            
            //retin numaru de studenti si angajati(in total) prin acest nr
            nr  ;
            cout << "Dati numele: ";
            cin >> n;
            cout << "Dati prenumele: ";
            cin >> p;
            cout << "Dati varsta: ";
            cin >> v;
            cout << "Dati departamentul: ";
            cin >> d;
            cout << "Dati salariul:";
            cin >> s;
            
            angajat[nr3] = Angajat(n, p, v, d, s);
            persoane[i] = &angajat[nr3];
            nr3  ;
            i  ;
            break;
        case 2:
                       //this search is working perfectly fine :)
            cout << "Introduceti numele persoanei: ";
            cin >> num;
            ok = 0;
            
            
            for (i = 0; i < nr; i  )
            {
                
                if ((num.compare(persoane[i]->returnName())) == 0)
                {
                    persoane[i]->afisare();
                }
                ok  ;
            }
            if (ok == 0)
                cout << "Aceasta persoana nu se afla in institutie:(";
            break;
        case 3:
            cout << "Introduceti numele pe care vreti sa il ste/rgeti:";
            cin >> num2;
            //here i want to delete an element, but when this is running will delete everything from my class:(
            for (i = 0; i < nr; i  )
            {
                if (num2.compare(persoane[i]->returnName()) == 0)
                {
                    persoane[i]->~Persoana(); 
                    nr--;
                    ok2  ;
                }
            }
            if (ok2 == 0)
            {
                cout << "Element not found";
            }
            else
            {
                cout << "Elementul a fost sters:";
            }
            break;
        case 4:         
            exit(0);
        }
    } while (choice != 4);
}


int main()
{
    menu();
}

In this program i create 2 child class from class Persoana, class Student and class Angajat ,in the menu at option 3 , it will ask you for a name to delete , my problem is that the function i created is deleting the whole class Persoana, i really dont know how to use destructors and abstract classes

CodePudding user response：

If you are instantiating Students and Angajats statically. You will not be able to delete them.

    Student student[40]; // static allocation of 40 students
    Angajat angajat[40]; // static allocation of 40 angajats
    Persoana * persoane[80]; // static allocation of 80 pointers to students and angajats base classes.

• First of all, you need to declare the Persoana destructor as virtual, to invoke derived classes destructors: virtual ~Persoana(){/*whatever*/}

• Instantiate the Students and Angajats dynamically. I.e: To create a new instance of Students you should use :

  Persoana* student = new Student();
  

And consider using the STL list : std::list<Persoana*>, ::push_back(..), and its iterators to search and delete elements.

that example creates a list of pointers to Persoana. Deleting the item of the list will NOT delete the item. For that, you have to use the delete operator.