awful

// ConsoleApplication2.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>
using namespace std;


int factorial(unsigned int a)
{
    if (a== 0)
        return 1;
    else
    {
        unsigned int i = 1;
        unsigned long int sum = 1;
        while (i <= a)
        {
            sum = sum*i;
            i++;
        }
        //cout << sum << "\n";
        return sum;
    }
}

int main()
{
    double xval, yval, eps, sum, sumprev;
    unsigned int i;
    cout << "Enter a value for x: ";
    cin >> xval;
    eps = 0;
    while (eps != 1 && eps != 2 && eps != 3)
    {
        cout << "\nChoose a value for epsilon for computing sin(x):\n1) 0.1\n2) 0.01\n3) 0.001\n";
        cin >> eps;
    }
    if (eps == 1)
        eps = 0.1;
    else if (eps == 2)
        eps = 0.01;
    else if (eps == 3)
        eps = 0.001;
    sum = 0;
    sumprev = 99;
    i = 0;
    while (abs(sum - sumprev) > eps)
    {
        if (2 * i + 1 > 13)
        {
            cout << "Maximum factorial reached\n"; //Cannot compute factorials over 14 due to size limit of long type.
            sumprev = sum;
        }
        else
        {
            sumprev = sum;
            sum = sum + (pow(-1, i) / factorial(2 * i + 1))*pow(xval, 2 * i + 1);
            cout << "at n=" << i << ", sin(" << xval << ") = " << sum << "\n";
            i++;
        }
    }

    sum = 0;
    for(unsigned int cosLoopI = 0; cosLoopI <= 7; cosLoopI++) //Cannot compute factorials over 14 (2*7) due to size limit of long type.
    {
        sum = sum + (pow(-1, cosLoopI) / factorial(2 * cosLoopI))*pow(xval, 2 * cosLoopI);
        cout << "at n=" << cosLoopI << ", cos(" << xval << ") = " << sum << "\n";
    }
}