#include <cstdlib>
#include <iostream>
#include <math.h>
#define RADTODEG(Rad) ((180.0 * Rad) / PI)
#define PI 3.14159

using namespace std;

int main(int argc, char *argv[])

{
   float a;
   float b;
   float c;
   float d; //angle
   float e; //opposite
   float f;
   float g;
   float h;
   int n;
   int i;
   unsigned long long factorial;
   int o;

    cout << "Please select on of the following options \n 1. Calculate the circumference of a circle \n 2. The area of a circle \n 3. The Hypotenuse of a triangle and the Opposite \n 4. Calculate the factorial of a Number.\n";
    cin >> a;

    if (a==1){
       cout << "Please Input the radius of the Circle\n";
       cin >> b;
       c = (2*PI*b);
       cout << "The Circumference of the circle is :";
       cout << c;
       }
    else if (a==2){
       cout << "Please Input the radius of the Circle\n";
       cin >> b;
       c = (PI*(b*b));
       cout << "The Area of the circle is :";
       cout << c;
       }
    else if (a==3){
       cout << "Please input Angle";
       cin >> d;
       cout << "Please input Opposite";
       cin >> e;
       g = sin(d*PI/180);
       h = (e/g);
       cout << h;
       }
       //IAN AFTER THIS POINT IS WHERE I NEED TO PUT IT
    else if (a==4){
        cout << "Please input a number: ";
        cin >> n;

        if (n < 1)
        {
            cout << "Sorry, number must be positive.\n";
        }
        else if (n > 65)
        {
            cout << "Sorry, can't handle a number bigger than 65 with only 64 bits for the result\n";
        }
        else
        {
            factorial=1;
            for (i=n; i>0; i--)
            {
                factorial *= i;
            }
            cout << "The factorial of " << n << " is " << factorial << "\n";
        }
    else cout << "Incorrect Input";
}