Подключить словарь к "виселице"

#include <vector>
#include <iostream>
#include <string>
#include <algorithm>
#include <ctime>
using namespace std;
 
int main()
{
    const int MAX_WRONG = 8;
    vector<string>words;
    words.push_back("GUESS");
    words.push_back("HANGMAN");
    words.push_back("DIFFICULT");
    srand((time(0)));   
    random_shuffle(words.begin(), words.end());
    const string THE_WORD = words[0];
    int wrong =0;
    string soFar(THE_WORD.size(),'-');
    string used = "";
    cout<<"Welcome! Good luck!"<<endl;
    while ((wrong < MAX_WRONG) && (soFar != THE_WORD)) {
        cout<<"/n/nYou have "<< (MAX_WRONG - wrong);
        cout<<" incorrect guesses left." <<endl;
        cout<<"You've used the following: "<< used << endl;
        cout << "So far? the word is:" << soFar << endl;
        char guess;
        cout << "\nEnter you guess:"; cin >> guess;
        guess = toupper (guess);
        while (used.find(guess)!=string::npos) {
            cout << "\n You've alredy guessed " << guess << endl;
            cout <<"Enter you guess:"; cin >> guess;
            guess = toupper(guess);
        }
        used +=guess;
        if (THE_WORD.find(guess) != string::npos) {
            cout << "that's rigt! " << guess << "is in the word.\n";
            for(int i = 0; i < THE_WORD.length(); ++i) {
                if (THE_WORD[i] == guess) {
                soFar[i] = guess;
                }
            }
        }else {
            cout << "Sorry, " << guess << " isn't in the word.\n";
            ++wrong;
        }
    }
    system("pause");
    return 0;
}

string buff[5];