Help with math tutor

[Sammiiee77]

hey guys I'm writing a math tutor program and i need it to keep track of the number of correct scores as well as number tries and i also want to have 5 answer options, i have the basis of the code but the others elude me.
I'm also trying to write this without any global variables. thanks.
here's what i have so far

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

using namespace std;

char Menu();                              //prototypes
void difficulty(int &);
void generate(double &, double &, int );
void addition(double &, double, double);
void subtraction(double &, double, double);
void multiplication(double &, double, double);
void division(double &, double, double, char);
void Ans(double &);



int main()
{
	double correctans, num1, num2;
	char choice;
	char line[80];
	int diff; 

	time_t now = time(0);
	string name;
	srand(now);  // Seed the random number generator.

	//cout << ctime(&now) << endl;

	cout << "what is your first and last name " << endl;
	getline(cin, name);

	for (unsigned i = 0; i < name.length(); i++)
		if (name[i] == ' ') name[i] = '_';

	name += ".txt";
	cout << endl << endl << endl;

	cout << "Welcome to the Math Skills Program " << endl;
	cout << "This program allows you to practice your math skills" << endl;
	cout << "Choose what to practice in the menu shown below." << endl;
	cout << endl << endl << endl;

	difficulty( diff);



	bool test = true; 
	while (test)
	
	{
		
		now = time(0);
//		cout << endl << "Problem start time:" << ctime(&now) << endl;

		generate(num1, num2, diff);
		choice = Menu();

		switch (choice)
		{
		case 'a': 
			addition(correctans, num1, num2);
			break;

		case 'b': 
			subtraction(correctans, num1, num2);
			break;

		case 'c': 
			multiplication(correctans, num1, num2);
			break;

		case 'd': 
			division(correctans, num1, num2, choice);
			break;

		case 'q': test = false;// The user chose to quit the program.
			cout << "Thank you for using Math Tutor program.\n\n";
			return 0;
			break;
		}

	}
	if (choice != 'q')
	{
		cout << "incorect input please try again" << endl;
		cin >> choice; // Loop again
	}
	 return 0;

}

char Menu()
{
	char choice;

	{
		cout << "Arithmetic Practice program\n" << endl;


		// Display the menu and get a choice.

	
		//cout << "------------------------------\n";
		cout << "---------------------------------------------------------" << endl;
		cout << "ARITHMETIC PRACTICE PROGRAM " << endl;
		cout << "MAIN MENU" << endl;
		cout << "-------------------------------------------------------- - " << endl;
		cout << "a. Addition \n";
		cout << "b. Subtraction\n";
		cout << "c. Multiplication\n";
		cout << "d. Division\n";
		cout << "q. Quit the program\n";
		cout << "------------------------------\n";
		cout << "Enter your choice (a b c d q): ";
		cin >> choice;
	}

	// Validate the choice.
	choice = tolower(choice);
	if (choice >= 'a' && choice <= 'd' || choice == 'q')
		cout << "You entered: '" << choice << "', your input is valid " << endl;
	else

	{
		cout << "The valid choices are a, b, c, "
			<< "d, and q. Please choose: ";
		cin >> choice;
	}
	cout << endl;
	return choice;
}

void difficulty(int & diff)
{
	//double studentans;
	char line[80];

	cout << "Select diffculty. Please choose" << endl;
	cout << " 1 for 1 digit\n"
		<< " 2 for 2 digits\n"
		<< " 3 for 3 digits\n"
		<< " 4 for 4 digits\n"
		<< " 5 for 5 digits\n"
		<< endl;
	cout << endl << "> ";

	cin >> line;
	diff = atoi(line);

	while (diff < 1 || diff >5)
	{
		cout << "Enter 1-5 only " << endl;
		cin >> line;
		diff = atoi(line);
		cin.clear();
		cin.ignore(1000, '\n');
	}

}

void generate( double & num1, double & num2, int diff)
{
	int min, max;
	min = pow(10., diff - 1);
	max = pow(10., diff);

	num1 = min + rand() % (max - min);
	num2 = min + rand() % (max - min);

}


void Ans(double & correctans)
{
	double studentans;
	// char choice;
	// if (choice >= 'a' && choice <= 'd')
	// {
		cin >> studentans;
		if (studentans == correctans)
			cout << "\n\nCongratulations! That's right.\n\n";
		else
			cout << "\n\nSorry, the correct answer is " << correctans << ".\n\n";
	// }
}

void addition(double & correctans, double num1, double num2)
{
	double studentans; //Generate two random numbers in the range 1 - 500.

	cout << "Prepare to add" << endl;
	
	//difficulty(num1, num2);

	// num1 and num2 haven't been randomly generated yet

	correctans = num1 + num2;

	// Display the problem.
	cout << "\n\n";
	cout << " " << setw(4) << num1 << endl;
	cout << " +" << setw(4) << num2 << endl;
	cout << " " << "----" << endl;
	cout << " ";

	Ans(correctans);
}


void subtraction(double & correctans, double num1, double num2)
{
	double studentans;
	//difficulty(num1, num2);

	//if ('h' : num2 > num1) //num2 = 1 + rand() % 999;
	correctans = num1 - num2;

	// Display the problem.
	cout << "\n\n";
	cout << " " << setw(8) << num1 << endl;
	cout << " -" << setw(8) << num2 << endl;
	cout << " " << "----" << endl;
	cout << " ";

	Ans(correctans);
}

void multiplication(double & correctans, double num1, double num2)
{
	double  studentans;

	//difficulty(num1, num2);

	correctans = num1 * num2;

	cout << "\n\n";
	cout << " " << setw(4) << num1 << endl;
	cout << " *" << setw(4) << num2 << endl;
	cout << " " << "----" << endl;
	cout << " ";
	
	Ans(correctans);

}

void division(double & correctans, double num1, double num2, char choice)
{
	double studentans;

	num1 = num2 * num1;
	//difficulty(num1, num2);
	/*if (choice == 'b')
	{
		num2 = 1 + rand() % 9;
		num1 = num2 * (rand() % 50 + 1);
	}
	if (choice == 'm')
	{

		num2 = 1 + rand() % 20;
		num1 = num2 * (rand() % 100 + 1); 
	}
	else if (choice == 'h')
	{

		num2 = 1 + rand() % 15;
		num1 = num2 * (rand() % 110 + 1);
	}
	*/

	// Calculate the correct answer.
	correctans= num1 / num2;

	cout << "\n\n";
	cout << " " << num1 << " / " << num2 << " = ";

	Ans(correctans);

}