GameManager.cpp
Code:
#include "ShopClass.h"
#include "BattleClass.h"
#include "GameManager.h"
#include <iostream>
#include <cctype>
using namespace std;

void GameManager::Manager()
{
     int money = 200;
     int lives = 3;
     int attack = 0;
     int defense = 0;
     ShopClass shop;
     BattleClass battle;
     cout << "Current Status:\n";
     cout << "Money: $" << money << "\n";
     cout << "Lives: " << lives << "\n";
     cout << "Attack Points: " << attack << "\n";
     cout << "Defense Points: " << defense << "\n";
     cout << "Would you like to visit the shop or battle robots?\n(Please enter either Shop or Battle)\n";
     cin >> ShopBattle;
     
     if (ShopBattle == "Shop" || ShopBattle == "shop") {
                    shop.Shop();
     } else if (ShopBattle == "Battle" || ShopBattle == "battle") {
            battle.Battle();
     } else {
            cout << "Error: Invalid Input";
     }
}

int GameManager::GetMoney()
{
    return money;
}
int GameManager::GetAttack()
{
    return attack;
}
int GameManager::GetDefense()
{
    return defense;
}
int GameManager::GetLives()
{
    return lives;
}

void GameManager::AddMoney(int amount)
{
     money =+ amount;
     if (money < 0)
          money = 0;
}

void GameManager::Lives()
{
     GameManager manager;
     lives =- 1;
     if (lives == 0)
        cout << "Game Over\n";
        cout << "Would you like to start again? (y or n)";
        cin >> restart;
        if (tolower(restart) == 'y') {
           money = 200;
           lives = 3;
           attack = 0;
           defense = 0;
           manager.Manager();
        } else if (tolower(restart) == 'n') {
               
        } else {
               cout << "Error: Invalid Input\n";
               manager.Lives();
        }
}

void GameManager::AddAttack(int amount)
{
     attack =+ amount;
}

void GameManager::AddDefense(int amount)
{
     defense =+ amount;
}
..and an example of code that needs to use some of the variables
Code:
 if (manager.GetAttack() >= 1){
           cout << "Attack Successful\nYou Won $200\n\n";
           manager.AddMoney(200);           
        } else {
          cout << "You Lost\n\n";
          manager.Lives();
        }