(C++) Vector elements seem to disappear after for loop ends - c++

Question

I'm extremely new to C++ (even newer to OOP) and I'm doing my first project that doesn't take place within one .cpp file. I've run into a seemingly simple issue where my vector data seems to be disappearing.
Code chunk inside main.cpp's main function:
vector<Horse> HorseStable(horseAmount); // creating an vector of horse objects based on user input horseAmount
for (int i = 0; i < horseAmount; i++) // sets name for each horse and rider
{
string nameString = "";
string riderString = "";
cout << "Enter name for horse #" << (i + 1) << ": ";
cin >> nameString;
HorseStable[i].setName(nameString);
cout << "Enter name for rider of " << nameString << ": ";
cin >> riderString;
HorseStable[i].setRider(riderString);
system("cls");
}
HorseStable[0].printName(); // a test to see if the horse name stayed inside the vector (it did not)
Entire Horse.h file:
#pragma once
#include <iostream>
#include <string>
#include <stdlib.h>
#include <time.h>
class Horse
{
private:
std::string name;
std::string rider;
public:
// these three ints were supposed to be private, but I couldn't access
// maxRunningDistPerSecond as a displayHorse() function parameter from main
// maybe figuring out my first issue will help with this, as I was attempting
// HorseStable[0].displayHorse(maxRunningDistPerSecond)
int maxRunningDistPerSecond;
int distanceTraveled;
int racesWon;
Horse() // default constructor
{
std::string name = " ";
std::string rider = " ";
int maxRunningDistPerSecond = 100;
int distanceTraveled = 0;
int racesWon = 0;
};
int runASecond(int, int);
int sendToGate(int);
void displayHorse(int);
std::string setName(std::string); // sets the horse name based on user input from main.cpp variable
std::string printName(); // simply prints the horse name, I don't believe my issue is here
std::string setRider(std::string);
std::string printRider();
};
Code chunk inside Horse.cpp:
std::string Horse::setName(std::string nameString) // takes user input for horse name
{
Horse::name = nameString;
return std::string(nameString);
}
std::string Horse::printName() // prints the horse's name
{
return std::string(name);
}
setName() and getName() work perfectly within my for loop inside main.cpp, but all data seems to disappear when I attempt them after the loop ends. I've looked for hours for solutions, but had to revert to this stable build after nothing worked. I'm not very good with pointers and passing by reference, but these seem to be the only things that will work. Is it possible that I was using pointers wrong? Should I be creating a vector of Horse pointers, rather than a vector of actual Horse objects?
My other issue:
If you've noticed my public members that are supposed to be private in Horse.h, I cannot access them when private as parameters from functions called in main. This makes some sense, as my function call in main looked like this:
HorseStable[0].displayHorse(distanceTraveled)
I'm not sure how I could refer to each element of the vector within the Horse class, which seems like the only way distanceTraveled would be reachable as private. My professor wants the variables in question to be private, which makes this an issue. The user defines the amount of Horse objects, which means I can't just declare a few named Horses and simply displayHorse(distanceTraveled) them.
Function declaration from Horse.cpp:
void Horse::displayHorse(int distanceTraveled) // attempts to show a graphic of the race progress
{
if (distanceTraveled >= 50)
{
std::cout << "|-> |" << " " << name << ", ridden by " << rider;
}
else if (distanceTraveled >= 100)
{
std::cout << "|--> |" << " " << name << ", ridden by " << rider;
}
else if (distanceTraveled >= 150)
{
std::cout << "|---> |" << " " << name << ", ridden by " << rider;
} // this goes on up to 1000, but this is all that's necessary for posting
I apologize if my formatting isn't up to par, but this assignment has really been stressing me out. I've been understanding all the new material, but it always seems like pointers and referencing are the things that render my assignments unusable.