Do damage help

[Orval]

In my classes, my damage script does not work. I think it might be because classes cant access other classes? I dont know, my book only had a 2 chapters over classes. I do these daily programs I make up just to help me out later on. There are two things I need help with.

1) How to get the damage() and hurt() functions to work.
2) Is there a way to make it one answer for the if(answer == "Yes" || answer == "yes" || answer == "YES")? I tried using toupper(), but it didnt work. (My book only mentioned what toupper did, not how to use it). This is how i used it: answer = (string)toupper();.

#include <iostream>
#include <string>
#include <ctime>
#include <cstdlib>

using namespace std;



class Player
{
    int health = 100;
    int Energ = 100;
public:
    int GetHealth();
    void damage(const int&  x);
    int GetEnergy();
private:
    int pHealth = health;
    int Energy = Energ;
};

int Player::GetHealth()
{
    return pHealth;
}

void Player::damage(const int&  x)
{
    srand(time(0));
    int num = x;
    int y = rand()%20;
    num = num - y;
    Energy = Energy - 10;
}

int Player::GetEnergy()
{
return Energy;
}

class Enemy
{
    int heal = 100;
public:
    void hurt(const int& y);
    int GetHeal();
private:
    int eHeal = heal;
};

    void Enemy::hurt(const int& y)
    {
        srand(time(0));
        int r = y;
        int d = rand()%20;
        r = r - d;
    }

    int Enemy::GetHeal()
    {
        return eHeal;
    }

int main()
{
    Player Ron;
    Enemy Obama;
    int x = Obama.GetHeal();
    int R = Ron.GetHealth();
    cout << "\t\t\t\tTesting\n\n";

    string answer;
    do
    {
        cout << "\nYour Health is " << Ron.GetHealth() << ", and your Energy is " << Ron.GetEnergy();
        cout << "\nObama's health is " << Obama.GetHeal();
        cout << "\n\nWhat would you like to do? 1] Attack. 2] Run. 3] Surrender\n";
        cin >> answer;
        if(answer == "1")
        {
            if(Ron.GetEnergy()<=0)
            {
cout << "\n\nYou ran out of energy, and have been killed by Obama\n\n";
break;
            }
            string answer2;
            cout << "\n\nAre you sure you want to attack?\n";
            cin >> answer2;
            if(answer2 == "Yes" || answer2 == "yes" || answer2 == "YES")
            {
                Ron.damage(x);
                cout << "\nYou attacked Obama.\n";
            }
            else if(answer2 == "No" || answer2 == "NO" || answer2 == "no")
            {
            }
            else
            {
                cout << "\nThat was not a valid option\n";
            }
        }
        if(answer == "2")
        {
            string answer3;
            cout << "\n\nAre you sure you want to run?\n";
            cin >> answer3;
             if(answer3 == "Yes" || answer3 == "yes" || answer3 == "YES")
            {
                if(Ron.GetHealth() > Obama.GetHeal())
                {
                    cout << "\n\nYou've ran away successfully!\n\n";
                    cout << "The End\n\n";
                    break;
                }
                else if(Ron.GetHealth() == Obama.GetHeal())
                {
                    int luck;
                    luck = 1+rand()%2;
                    if(luck == 1);
                    {
                        cout << "\nYou escaped!\n";
                        cout << "\nThe End\n\n";
                        break;
                    }
                    if(luck == 2)
                    {
                        cout << "\Obama caught you.\nTheEnd?\n\n";
                        break;
                    }
                }
                else if(Ron.GetHealth() < Obama.GetHeal())
                {
                    cout << "\Obama caught you.\nTheEnd?\n\n";
                        break;
                }
                else
                {
                    cout << "\n\nObama hacked the game?\n";
                }
            }
            else if(answer3 == "No" || answer3 == "NO" || answer3 == "no")
            {
            }
            else
            {
                cout << "\nThat was not a valid option\n";
            }
        }
        if(answer == "3")
        {
             string answer4;
            cout << "\n\nAre you sure you want to Surrender?\n";
            cin >> answer4;
            if(answer4 == "Yes" || answer4 == "yes" || answer4 == "YES")
            {
                cout << "Obama captured you\n";
                break;
            }
            else if(answer4 == "No" || answer4 == "NO" || answer4 == "no")
            {
            }
            else
            {
                cout << "\nThat was not a valid option\n";
            }
        }
        Obama.hurt(R);
    }while(x>0);

    if(Obama.GetHeal()<=0)
    {
        cout << "\n\nYou killed Obama!\n\nYou Won!\n\n";
    }
    else
    {
        cout << "\nThanks for playing!";
    }
}

Thanks, and if you find something that I shouldnt do in my program, please let me know. I'm trying really hard to become a good programmer in the future.