Reading objects from a text file

Question

I am reading objects from a text file and placing them in a vector. I am then trying to display them using a vector. I have the program working but not quite correctly. The problem I am having is the vector a collection of pointers and the objects are being overwritten and I am only getting the last two objects of the text file. Any idea on how to fix this so I can get all of the information from the text file not just the last two entries?

entities.txt

4
hero
Fred The Strong
100
The Outcast
30.89
22
18
9
6
villain
Scout
25
Goblin
3
0
villain
Arch Shaman
50
Orc
60
1
hero
Countess de Winter
100
none
200.00
9
11
19
14

main

#include "Entity.h"
#include "Hero.h"
#include "Villian.h"
#include <cstdlib>
#include <sstream>
#include <fstream>
#include <vector>

using namespace std;


int main(int argc, char** argv) {
    vector<Entity *> fileObjects;
    Hero hero1;
    Villian villian1;
ifstream readFile("entities.txt");
string line;
getline(readFile, line);
while(!readFile.eof())
{
    getline(readFile, line);
    if(line == "hero")
    {
        getline(readFile, line);
        hero1.name = line;
        getline(readFile, line);
        hero1.hp = stoi(line);
        getline(readFile, line);
        hero1.guild = line;
        getline(readFile, line);
        hero1.coin = stof(line);
        getline(readFile, line);
        hero1.strength = stoi(line);
        getline(readFile, line);
        hero1.dexterity = stoi(line);
        getline(readFile, line);
        hero1.faith = stoi(line);
        getline(readFile, line);
        hero1.wisdom = stoi(line);
        fileObjects.push_back(&hero1);
    }
    else if (line == "villain")
    {
        getline(readFile, line);
        villian1.name = line;
        getline(readFile, line);
        villian1.hp = stoi(line);
        getline(readFile, line);
        villian1.race = line;
        getline(readFile, line);
        villian1.level = stoi(line);
        getline(readFile, line);
        if(line == "0")
        {
            villian1.isBoss = false;
        }
        else
        {
            villian1.isBoss = true;
        }
        fileObjects.push_back(&villian1);
    }
    
}
readFile.close();

for(int i = 0; i < fileObjects.size(); i++)
{
    fileObjects[i]->display();
}
    return 0;
}

Entity header

#include <iostream>

using namespace std;

#ifndef ENTITY_H
#define ENTITY_H

class Entity {
public:
    string name;
    int hp;
    virtual void display();
    Entity(string name, int hp);
    Entity();
    Entity(const Entity& orig);
    virtual ~Entity();
private:

};

#endif /* ENTITY_H */

Entity source

#include "Entity.h"

Entity::Entity() {
    name = "";
    hp = 0;
}
Entity::Entity(string name, int hp)
{
    this->name = name;
    this->hp =hp;
}
void Entity::display()
{
    cout << "Name: " << name << endl;
    cout << "HP: " << hp << endl;
}
Entity::Entity(const Entity& orig) {
}

Entity::~Entity() {
}

Hero header

#include "Entity.h"

#ifndef HERO_H
#define HERO_H

class Hero:public Entity {
public:
    string guild;
    float coin;
    int strength;
    int dexterity;
    int faith;
    int wisdom;
    void display();
    Hero(string name, int hp, string guild, float coin, int strength, int dexterity, int faith, int wisdom);
    Hero();
    Hero(const Hero& orig);
    virtual ~Hero();
private:

};

#endif /* HERO_H */

Hero source

#include "Hero.h"

Hero::Hero() {
    guild = "";
    coin = 0.0f;
    strength = 0;
    dexterity = 0;
    faith = 0;
    wisdom = 0;
}
Hero::Hero(string name, int hp, string guild, float coin, int strength, int dexterity, int faith, int wisdom):Entity(name, hp)
{
    this->guild = guild;
    this->coin = coin;
    this->strength = strength;
    this->dexterity = dexterity;
    this->faith = faith;
    this->wisdom = wisdom;
}
void Hero::display()
{
    Entity::display();
    cout << "Guild: " << guild << endl;
    cout << "Coin: " << coin << endl;
    cout << "Strength: "  << strength << endl;
    cout << "Dexterity: " << dexterity << endl;
    cout << "Faith: " << faith << endl;
    cout << "Wisdom: " << wisdom << endl;
}
Hero::Hero(const Hero& orig) {
}

Hero::~Hero() {
}

Villian header

#include "Entity.h"

#ifndef VILLIAN_H
#define VILLIAN_H

class Villian:public Entity {
public:
    string race;
    int level;
    bool isBoss;
    void display();
    Villian(string name, int hp, string race, int level, bool isBoss);
    Villian();
    Villian(const Villian& orig);
    virtual ~Villian();
private:

};

#endif /* VILLIAN_H */

Villian source

#include "Villian.h"

Villian::Villian() {
    race = "";
    level = 0;
    isBoss = false;
}
Villian::Villian(string name, int hp, string race, int level, bool isBoss):Entity(name, hp)
{
    this->race = race;
    this->level = level;
    this->isBoss = isBoss;
}
void Villian::display()
{
    Entity::display();
    cout << "Race: " << race << endl;
    cout << "Level: " << level << endl;
    cout << "Is A Boss: "  << isBoss << endl;
}
Villian::Villian(const Villian& orig) {
}

Villian::~Villian() {
}

Answer 1

The problem is that you are only pushing the same pointer to your Hero/Villain object onto your vector and you are overwriting the original object. Thus, when you print out the contents you are only ever printing out the same memory contents (which are being re-written as you read the entities file.)

Instead, you should either allocate a new Hero/Villain object on the heap (e.g. using new, or by creating a shared_ptr or unique_ptr.)

As a keen commenter points out, you do not want to push new Entity by value since you're relying on the polymorphic behavior of the Entity class and its derived classes [1].

1 - https://en.wikipedia.org/wiki/Object_slicing