/*
Maths Machine v0.3 - Same features just
more efficient... maybe lol
*/
#include <iostream>
#include <cmath>
#include <string>

void pause()
{
    using std::cout;
    using std::cin;

    cout << \"Press \'Enter\' key to continue...\";
    cin.sync ();
    cin.clear();
    cin.get();
    return;
}

int main()
{
    using std::cout;
    using std::cin;

    //variables
    std::string name;
    char op, choice;
    double num1, num2, num3, answer;

    //name
    cout << \"Enter your name: \";
    getline(std::cin, name);

    //menu
    cout << \"Welcome to Maths Machine \" << name << \"\n\n\";
    for(;;)
    {
        do
        {
            //Options
            cout << \"Maths Machine v0.3 Menu\n\";
            cout << \"  1. Simple Maths\n\";
            cout << \"  2. Square Roots\n\";
            cout << \"  3. Pythagoras\n\";
            cout << \"Enter a choice ('q' to quit): \";
            cin >> choice;

        } while( choice < '1' || choice > '3' && choice != 'q');

        //q = quit
        if(choice == 'q') break;

        cout << \"\n\n\";

        switch(choice)
        {
            case '1': //Option 1, Simple maths
                //Enter your numbers and operator for the calculation
                cout << \"Welcome to Simple Maths brought to you within the Maths Machine\n\";
                cout << \"Enter your first number: \n\";
                cin >> num1;
                cout << \"Enter your Operater (*,/,+,-): \n\";
                cin >> op;
divretry:
                cout << \"Enter you second number: \n\";
                cin >> num2;

                //addition
                if(op == '+')
                {
                    //calculation
                    answer = num1 + num2;
                    //answer
                    cout << \"The Answer to \" << num1 << op << num2 << \" = \" << answer << \"\n\";
                    break;
                }
                //subtraction
                if(op == '-')
                {
                    //calculation
                    answer = num1 - num2;
                    //answer
                    cout << \"The Answer to \" << num1 << op << num2 << \" = \" << answer << \"\n\";
                    break;
                }
                //multiplication
                if(op == '*')
                {
                    //calculation
                    answer = num1 * num2;
                    //answer
                    cout << \"The Answer to \" << num1 << op << num2 << \" = \" << answer << \"\n\";
                    break;
                }
                //division
                if(op == '/')
                {
                    //cannot divide 1st number with zero error
                    if(num2 <= 0)
                    {
                        cout << \"Sorry but you cannot have a number equal or less than zero [0] as you're second number.\n\";
                        goto divretry;
                    }
                    //calculation
                    answer = num1 / num2;
                    //answer
                    cout << \"The Answer to \" << num1 << op << num2 << \" = \" << answer << \"\n\";
                }
            case '2': //Option 2, Ssquare roots
                cout << \"Welcome to Square Roots brought to you within the Maths Machine\n\";
                //enter number you wish to find the square root of...
                cout << \"Enter the number you want to find the square root of: \n\";
                cin >> num1;

                //calculation
                answer = sqrt(num1);

                //answer
                cout << \"The square root of \" << num1 << \" = \" << answer << \"\n\";
                break;
            case '3': //Option 3, Pythagoras
                cout << \"Welcome to Pythagoras brought to you within the Maths Machine\n\";
again:
                //enter number of the longest side
                cout << \"Enter the length of the longest side running away from the 90 degree angle: \n\";
                cin >> num1;
again2:
                //enter length of the smallest side
                cout << \"Enter the length of the smaller side leading away from the 90 degree angle: \n\";
                cin >> num2;

                //error 1, longest side is too short
                if(num1 <= 0 || num1 <= num2)
                {
                    cout << \"Sorry, the inputted number for the longest side cannot be correct, enter a number above 0 and longer than the second side\" << \"\n\";
                    goto again;
                }
                //error 2, shortest side is too long
                if(num2 <= 0 || num2 >= num1)
                {
                    cout << \"Sorry the inputter number for the smallest side cannot be larger than the first or equal '0'!\" << \"\n\";
                    goto again2;
                }

                /*
                the pythagoras theory states that the length of
                a(the hypotenuse) = b(squared) + c(squared). But
                for our program we don't want the user to be left
                with the square number of the length. So we add the
                sqrt() function to automatically give the base
                length for the hypotenuse.
                */
                answer = sqrt((num1*num1) + (num2*num2));

                //answer
                cout << \"The length of the hypotenuse is \" << answer << \"\n\";
                break;
        }
        cout << \"\n\n\";
    }
        pause();
        return 0;
}