#include <iostream>
#include <cstdlib>
#include <ctime>
#include <string>
using namespace std;

float calculateNumbers(float a, int sign, float b){
  if(sign == 0){
      return a + b;
  }
  else if(sign == 1){
      return a - b;
  }
  else if(sign == 2){
      return a * b;
  }
  else if(sign == 3){
      return a / b;
  }
  else{
      return 1;
  }
}

string changeOperator(int sign){
   if (sign == 0){
       return "+";
   }
   else if (sign == 1){
       return "-";
   }
   else if (sign == 2){
       return "*";
   }
   else if (sign == 3){
       return "/";
   }
   else{
       return "?";
   }
}

int main()
{
    float a;
    float b;
    float c;
    float d;
    float res1;
    float res2;
    float res3;
    float result;
    int operator1;
    int operator2;
    int operator3;
    string str1;
    string str2;
    string str3;
    int counter = 0;
    int startValue;
    int endValue;
    string userOperator1;
    string userOperator2;
    string userOperator3;
    srand(time(nullptr));
    string userOperators;
    string inputLine;
    string op1, op2, op3;
    int puzzleChosen = rand() % 3185 + 1;
    bool isUserInputInvalid = false;
    string displayChar1;
    string displayChar2;
    string displayChar3;

    cout << "Enter the beginning solution to be printed:";
    cin >> startValue;
    cout << endl;
    cout << "Enter the end solution to be printed: ";
    cin >> endValue;
    cout << endl;

    for (a = 1; a <= 9; ++a)
    {
        for (b = 1; b <= 9; ++b)
        {
            for (c = 1; c <= 9; ++c)
            {
                for (d = 1; d <= 9; ++d)
                {
                    for (operator1 = 0; operator1 <= 3; ++operator1)
                    {
                        for (operator2 = 0; operator2 <= 3; ++operator2)
                        {
                            for (operator3 = 0; operator3 <= 3; ++operator3)
                            {
                                displayChar1 = changeOperator(operator1);
                                displayChar2 = changeOperator(operator2);
                                displayChar3 = changeOperator(operator3);
                                result = calculateNumbers(a, operator1, b);
                                result = calculateNumbers(result, operator2, c);
                                result = calculateNumbers(result, operator3 , d);

                                if (res3 == 24)
                                {
                                    ++counter;
                                    if (counter >= startValue && counter <= endValue)
                                    {
                                        cout << counter << ":" << a << " " << str1 << " " << b << " " << str2 << " " << c << " " << str3 << " " << d;
                                        cout << " = " << res3;
                                        cout << endl;
                                    }
                                    if (counter == puzzleChosen)
                                    {
                                        cout << "Puzzle chosen is #" << counter << ":" << a << " " << str1 << " " << b << " " << str2 << " " << c << " " << str3 << " " << d;
                                        cout << endl;
                                        cout << "The numbers to use are " << a << " " << b << " " << c << " " << d;
                                        cout << endl;
                                        cout << "Enter the three operators to be used (+, -, * or / ):" << endl;
                                        getline(cin, inputLine);
                                        op1=inputLine[0];
                                        op2=inputLine[1];
                                        op3=inputLine[2];
                                        // userOperators = userOperator1 + userOperator2 + userOperator3;
                                        // cout << userOperator1 << userOperator2 << userOperator3;
                                        userOperators = op1 + op2 + op3;
                                        cout << endl;
                                        if (str1 == op1 && str2 == op2 && str3 == op3)
                                        {
                                            cout << a << userOperator1 << b << " = " << res1 << endl;
                                            cout << res1 << userOperator2 << c << " = " << res2 << endl;
                                            cout << res2 << userOperator3 << d << " = " << res3 << endl;
                                            cout << "Well done!" << endl;
                                        }
                                        else if(userOperators.size() > 3 || userOperators.size() < 3){
                                            isUserInputInvalid = true;
                                            cout << endl;
                                            cout << "invalid number of characters entered, please try again";
                                            cout << endl;
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
    }
    return 0;
}