c++ dynamic allocatinon 2d array

Question

I want to make a dynamically allocated 2d array, but I don't really know how to do it. I've searched google and everything, but just couldn't make it work. My code so far is:

postaH.h:

#ifndef POSTAHH
#define POSTAHH
#include <vector>
#include <string>
#include <iostream>
#include "feladoH.h"

using namespace std;

class postaH : public feladoH{
  private:
          int szertekek[7];
          string szovegek[7];
          int a,b;
          int** szamosszesit;
          string d,c;
          string** szovosszesit;
  public:
         postaH();
         postaH(int szertekek[7], string szovegek[7],int,int,string,string);
         ~postaH();
         postaH(postaH& pos);
         int getSzertek();
         string getSzovegek();
         void setSzertek(int ir,int hsz,int szulev, int cir, int chsz,int surg, int suly);
         void setSzovegek(string nev,string varos,string utca,string cnev,string cvaros,string cutca,string cstipus);
         void hozzaad();
         void fajlbakiir();
};
#endif

postaS.cpp:

#include <string>
#include <iostream>
#include <fstream>
#include "postaH.h"

int seged = 0;

using namespace std;

postaH::postaH(){
          int szertekek[7];
          string szovegek[7];     
          int** szamosszesit;
          string** szovosszesit;
   }

postaH::postaH(int szertekek[7], string szovegek[7],int aa,int bb,string dd,string cc)     : a(aa),b(bb),d(dd),c(cc){
   this->szertekek[7] = szertekek[7];
   this->szovegek[7] = szovegek[7];
    szamosszesit = new int*[a];
for (int i = 0; i<a; i++){
        szamosszesit[i] = new int[b];
    }
    for (int i = 0; i<a; i++){
    for (int j = 0; j<b; j++){
        szamosszesit[i][j] = 0;
    }
szovosszesit = new string*[d];
for (int i = 0; i<d; i++){
    szovosszesit[i] = new string[d];
}
for (int i = 0; i<d; i++){
    for (int j = 0; j<c; j++){
        szovosszesit[i][j] = 0;
        }
}

postaH::~postaH(){
              delete [] szertekek;
              delete [] szovegek;
              for (int i = 0; i<a; i++){
                  delete [] szamosszesit[i];
                    } 
                    delete [] szamosszesit;
            for (int i = 0; i<d; i++){
                  delete [] szovosszesit[i];
                    } 
                        delete [] szovosszesit;
}

postaH::postaH(postaH& pos){
   this->szertekek[7] = pos.getSzertek();
   this->szovegek[7] = pos.getSzovegek(); 
    }

int postaH::getSzertek(){
return szertekek[7];
}

std::string postaH::getSzovegek(){
return szovegek[7];        
}

void postaH::setSzertek(int ir,int hsz,int szulev, int cir, int chsz,int surg, int suly){
 this->szertekek[0] = ir;
 this->szertekek[1] = hsz;
 this->szertekek[2] = szulev;
 this->szertekek[3] = cir;
 this->szertekek[4] = chsz;
 this->szertekek[5] = surg;
 this->szertekek[6] = suly;
}

void postaH::setSzovegek(string nev,string varos,string utca,string cnev,string cvaros,string cutca,string cstipus){
 this->szovegek[0] = nev;
 this->szovegek[1] = varos;
 this->szovegek[2] = utca;
 this->szovegek[3] = cnev;
 this->szovegek[4] = cvaros;
 this->szovegek[5] = cutca;
 this->szovegek[6] = cstipus;
}

void postaH::hozzaad(){

}

void postaH::fajlbakiir(){
 ofstream kezb;
 kezb.open ("kezbesitett.txt", ios::app);
 for( int i=0;i<7;i++){
      kezb << szovegek[i] << ",";
      kezb << szertekek[i] << ",";
      }
 kezb << "\n";
 kezb.close();
}

So my question is basically how should I make the declaration in the header file, and the constructors, destructor in the cpp file to work ?

Try from the very beginning to code "in English", those Hungarian function and variable names are not very readable. — Cartesius00
– Cartesius00, Commented Nov 30, 2012 at 11:46
basically i want to make 2 2d array, to put some of the stored data in it. the user gives data trough console, which is stored in the szertekek,szovegek array, and i want to store that data in a 2d array(szovosszesit,szamosszesit) so i can print the last 10 stored data. — JohnnnnnY
– JohnnnnnY, Commented Nov 30, 2012 at 11:47
A lot of context can be gleaned from the function and variable names. However since the general audiance cannot read Hungarian that context is lost. — graham.reeds
– graham.reeds, Commented Nov 30, 2012 at 11:56
I highly recommend against using "dynamic arrays" using pointers. A std::vector of vectors is much better. E.g. std::vector<std::vector<int>> szamosszesit; — Some programmer dude
– Some programmer dude, Commented Nov 30, 2012 at 11:57

graham.reeds · Accepted Answer · 2012-11-30 11:59:26Z

2

Generally if you are creating an array it is better to use a container suited to that task:

std::vector for a sequential container of items.
std::deque for a sequential container of items that needs updating from either end.
std::list for a sequential container that will be updated from any point in the sequence.

answered Nov 30, 2012 at 11:59

graham.reeds

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1 Comment

graham.reeds Over a year ago

My definition of sequential is probably different from the mathematical. I am using it to describe that you can easily enumerate from [0..n].

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