C++ - Segmentation fault when returning a string - c++

Question

I have this class
#include "Room.h"
#include "Book.h"
#include <cstdlib>
#include <iostream>
static int book_counter = 100;
//Constructors
Book::Book() {
for(int i = 0; i < 13; i++) {
this->customer_name += 97 + rand() % 26;
}
this->arrival = rand() % 30;
this->duration = 1 + (rand() % 10);
this->ppl = 1 + rand() % 5;
this->room = nullptr;
this->book_code = book_counter++;
}
Book::Book(std::string nm, int arr, int dur, int ppl) {
this->customer_name = nm;
this->arrival = arr;
this->duration = dur;
this->ppl = ppl;
this->room = nullptr;
this->book_code = book_counter++;
}
//Methods
int Book::getArr() {
return arrival;
}
int Book::getDur() {
return duration;
}
int Book::getPpl() {
return ppl;
}
void Book::anathesi(Room* x) {
this->room = x;
}
int Book::getBookCode() {
return book_code;
}
Room* Book::getRoom() {
return room;
}
std::string Book::getCustomerName() {
return customer_name;
}
which includes a string getter method getCustomerName().
When I call this method on main, via an instance created via the first constructor, everything works fine. On the other hand, if the instance is created via the second constructor, the method will cause a segmentation fault.
It seems like customer_name has an infinite length, thus causing a segmentation fault when I try to return it.
The method is called in main with this line of code:
cout << hotel.getBooks(i)->getBookCode() << " " << hotel.getBooks(i)->getCustomerName()
<< " " << hotel.getBooks(i)->getRoom()->getRoomCode() << "\n";
I am new into C++, so please elaborate my fault as much as needed.
The header file for class Book:
#ifndef PROJECT_BOOK_H
#define PROJECT_BOOK_H
#include <string>
class Room;
class Book {
protected:
std::string customer_name;
int book_code;
int arrival;
int duration;
int ppl;
Room* room;
public:
Book();
Book(std::string nm, int arr, int dur, int ppl);
void anathesi(Room* x);
int getArr();
int getDur();
int getPpl();
int getBookCode();
std::string getCustomerName();
Room* getRoom();
};
#endif //PROJECT_BOOK_H
In Hotel.h:
private: std::vector<Book*> books;
public: Book* getBooks(int i);
In Hotel.cpp:
Book* Hotel::getBooks(int i) {
return books[i];
}

Answer 1

Found the problem and fixed it.
I was creating instances with this piece of code:
Book obj(onoma, afiksh - 1, meres, arithmos);
which caused the segmentation I said.
I changed this to:
Book *obj = new Book(onoma, afiksh - 1, meres, arithmos);
and fixed the problem. Thanks for your time and help.
Unfortunately, I don't really know why this works, but it does, everything functions properly. Therefore I guess I'll have to look at new documentation.