#include <iostream>
#include <iomanip>
#include <fstream>
#include <string>
#include <cstdlib>
#include <ctime>
#include <cmath>

using namespace std;
int choice, problems, problemsDone, i, num1, num2, correct;
float userAnswer, actualAnswer, grade;
double dividedAnswer;
string name;
char ch;
void menu();

int main()
{
	cout << "Math Tutor \n";
	cout << "\n";
	cout << "What is your name? \n";
	getline(cin, name);
	cout << "Welcome, " << name << "!\n";

	menu();

	cin.get(ch);
	ch = cin.get();

}
void menu()
{
	cout << "\n";
	cout << "Please choose one of the following options! \n";
	cout << "1. Addition \n";
	cout << "2. Subtraction \n";
	cout << "3. Multiplication \n";
	cout << "4. Division \n";
	cout << "5. Quit \n";
	while (true)
	{
		if (!(cin >> choice))
		{
			cout << "Input must be an integer. Please try again. \n";
			cin.clear();
			cin.ignore();
			menu();
		}
		switch (choice)
		{
		case 1: //addition
			cout << "How many problems would you like? \n";
			cin >> problems;
			if (problems > 1)
			{
				do
				{
					srand(time(0));
					num1 = rand() % 100;
					num2 = rand() % 100;
					cout << "What is " << num1 << "+" << num2 << "?\n";
					cin >> userAnswer;
					actualAnswer = num1 + num2;
					if (userAnswer == actualAnswer)
					{
						cout << "Good job! \n";
						++correct;
					}
					else {
						cout << "Incorrect, the correct answer is " << actualAnswer << ".\n";
					}
					++problemsDone;
				} while (problemsDone < problems);
				grade = (correct * 100) / problems;
				cout << "You got a " << grade << "%. You got a total of " << correct << " correct out of " << problems << ".\n";
				break;
			}
			else
			{
				cout << "Invalid entry. \n";
				menu();
			}
			break;


		case 2: //subtraction
			cout << "How many problems would you like? \n";
			cin >> problems;
			if (problems > 1)
			{
				do
				{
					srand(time(0));
					num1 = rand() % 100;
					num2 = rand() % 100;
					cout << "What is " << num1 << "-" << num2 << "?\n";
					cin >> userAnswer;
					actualAnswer = num1 - num2;
					if (userAnswer == actualAnswer)
					{
						cout << "Good job! \n";
						++correct;
					}
					else {
						cout << "Incorrect, the correct answer is " << actualAnswer << ".\n";
					}
					++problemsDone;
				} while (problemsDone < problems);
				grade = (correct * 100) / problems;
				cout << "You got a " << grade << "%. You got a total of " << correct << " correct out of " << problems << ".\n";
			}
			else {
				cout << "Invalid entry. \n";
				menu();
			}
			break;

		case 3: //multiplication
			cout << "How many problems would you like? \n";
			cin >> problems;
			if (problems > 1)
			{
				do
				{
					srand(time(0));
					num1 = rand() % 100;
					num2 = rand() % 100;
					cout << "What is " << num1 << "*" << num2 << "?\n";
					cin >> userAnswer;
					actualAnswer = num1 * num2;
					if (userAnswer == actualAnswer)
					{
						cout << "Good job! \n";
						++correct;
					}
					else {
						cout << "Incorrect, the correct answer is " << actualAnswer << ".\n";
					}
					++problemsDone;
				} while (problemsDone < problems);
				grade = (correct * 100) / problems;
				cout << "You got a " << grade << "%. You got a total of " << correct << " correct out of " << problems << ".\n";
				break;
			}
			else
			{
				cout << "Invalid entry. \n";
				menu();
			}
			break;

		case 4: //division
			cout << "How many problems would you like? \n";
			cin >> problems;
			if (problems > 1)
			{
				do
				{
					srand(time(0));
					num1 = rand() % 100 + 1;
					num2 = rand() % 100 + 1;
					cout << "What is " << num1 << "/" << num2 << "?\n";
					cin >> userAnswer;
					dividedAnswer = (double)num1 / num2;
					if (userAnswer == dividedAnswer)
					{
						cout << "Good job! \n";
						++correct;
					}
					else {
						cout << "Incorrect, the correct answer is " << actualAnswer << ".\n";
					}
					++problemsDone;
				} while (problemsDone < problems);
				grade = (correct * 100) / problems;
				cout << "You got a " << grade << "%. You got a total of " << correct << " correct out of " << problems << ".\n";
				break;
			}
			else {
				cout << "Invalid entry.\n";
				menu();
			}
			break;

		case 5: //quit
			cout << "Goodbye!" << endl;
			return;

		default: //handler
			cout << "Incorrect, please try again. \n \n";
			menu();
			break;
		}
	}
}