I'm freeing memory twice - C++ - c++

Question

I have done this program where I check if my 'date' class is correct. The problem is that when I run my test program, it returned my the following error:
Error in `./bin/test': double free or corruption (fasttop): 0x00000000019c07c0 *
The job of this class is read and store a 'date'(a year) and a few events (allocated in a string array). For example, a object of this class would be: 1998 EVENT1 EVENT2 EVENT3.
Operator >> reads the next format:1908#Fantasmagorie#The Taming of the Shrew#The Thieving Hand#The Assassination of the Duke of Guise#A Visit to the Seaside
Well, my problem is that I'm deleting some pointer twice or freeing some memmory twice, I have tried a lot of things but I don't know how to fix it (as you can see on my code, I have already tried to set all pointers to 0 when I delete them.):
Date class .h
#ifndef _date_HISTORICA_
#define _date_HISTORICA_
#include <iostream>
#include <string>
#include <cassert>
using namespace std;
class date{
private:
int year;
int eventsNum;
int reserved;
string * str;
void resize(int r);
public:
date();
//date(int a, string *s, int n);
date(const date& d);
~date();
int getAge();
void addEvent(string& s);
friend ostream& operator<<(ostream& os, const date& d);
friend istream& operator>>(istream& is, date& d);
};
#endif
Date Class Code:
#include<iostream>
#include<string>
#include<fstream>
#include<sstream>
#include<date.h>
using namespace std;
void date::resize(int r)
{
assert(r>=0);
if(r!=this->reserved)
{
if(r!=0)
{
string * aux = new string[r];
if(this->reserved>0)
{
int min=this->reserved<r?this->reserved:r;
for(int i=0; i<min; i++)
aux[i]=this->str[i];
delete[] this->str;
this->str=NULL;
}
this->str=aux;
this->reserved=r;
if(this->reserved<this->eventsNum)
this->eventsNum=this->reserved;
} else
{
if(this->reserved>0)
{
delete[] this->str;
this->str=NULL;
}
this->year=0;
this->eventsNum=0;
this->reserved=0;
}
}
}
date::date() : year(0), eventsNum(0), reserved(0), str(0){}
date::date(const date& d)
{
this->year=d.year;
this->eventsNum=d.eventsNum;
this->reserved=d.reserved;
this->str=new string[this->reserved];
for(int i=0; i<this->eventsNum; i++)
this->str[i]=d.str[i];
}
date::~date()
{
this->year=0;
this->eventsNum=0;
this->reserved=0;
if(this->str)
delete[] this->str;
this->str=NULL;
}
int date::getAge(){return this->year;}
ostream& operator<<(ostream& os, const date& d)
{
os << d.year;
for(int i=0; i<d.eventsNum; i++)
os << '#' << d.str[i];
os << endl;
return os;
}
void date::addEvent(string& s){
if (this->eventsNum == this->reserved){
if (this->eventsNum==0)
resize(1);
else
resize(2*this->reserved);
}
this->str[eventsNum]=s;
eventsNum++;
}
istream& operator>>(istream& is, date& d)
{
string line; char c;
is >> d.year >> c;
getline(is, line);
int n=1;
for(int i=0; i<line.length(); i++)
if(line[i]=='#')
n++;
d.eventsNum=n;
d.reserved=d.eventsNum;
delete[] d.str;
d.str=NULL;
d.str=new string[n];
stringstream ss(line);
for(int i=0; i<n; i++)
getline(ss, d.str[i], '#');
return is;
}
Test Program Class:
#include<iostream>
#include<fstream>
#include<cronologia.h>
#include<date.h>
using namespace std;
int main(int argc, char * argv[]){
cout << "STATE: IN PROGRESS" << endl;
cout << "TEST: (2)" << endl;
date d;
ifstream f("./data/name.txt");
while(f >> d)
{
cout << d;
}
date d1;
cin >> d1;
d=d1;
cout << d << endl;
}
Example file (wich should be read by date clas):
1900#Sherlock Holmes Baffled#The Enchanted Drawing
1901#Star Theatre#Scrooge, or, Marley's Ghost
1902#A Trip to the Moon
1903#The Great Train Robbery#Life of an American Fireman
1904#The Impossible Voyage
1905#Adventures of Sherlock Holmes; or, Held for Ransom
1906#The Story of the Kelly Gang#Humorous Phases of Funny Faces#Dream of a Rarebit Fiend
1907#Ben Hur#L'Enfant prodigue
1908#Fantasmagorie#The Taming of the Shrew#The Thieving Hand#The Assassination of the Duke of Guise#A Visit to the Seaside
Im so sorry for my English!!! :,(

Answer 1

Since there is no assignment overloading in your code, in the line
d=d1;
All the members of d1 will be copied to a new object d by value. Hence there will be two copies of the object date which have the same reference value in their member str. Those two will eventually get out of scope and both will be destructed. The first one will free the allocated memory while the other will try to free that same reference and that is why you get the error.

Answer 2

You need a copy assignment operator:
void swap(date& other)
{
using std::swap;
swap(year, other.year);
swap(eventsNum, other.eventsNum);
swap(reserved, other.reserved);
swap(str, other.str);
}
date::date(const date& d) : year(other.year), eventsNum(other.eventsNum), reserved(other.reserved), str(new string[other.reserved])
{
for(int i = 0; i < this->eventsNum; i++)
this->str[i] = d.str[i];
}
date& date::operator = (const date& d)
{
swap(*this, d);
return *this;
}
Might also be nice to provide a move constructor..