/*
Written by Andre Jones under Creative Commons license
Lean version, all in same file
Revision by Walley on 13/6/05 --Added program loopability
**Edited by Andre Jones on 14-15/6/05 -- 
--Added new formulae
--Added variable name explanations
**Edited by Andre Jones on 16/6/05 --
--Added new forumlae
--"Prettycized" menu
--Added documentation of variables
--Fixed some print errors
--Added speed of sound
--cleaned menu
**Edited 18/6/05
--Replaced macro's with single class and static functions
**Edited 19/6/05
--Replaced classes with namespace, put headers into main file
**Edited 19/6/05
--Added reverse functionality to physics functions
*/
#include <iostream>
#include <string>

using namespace std;
int y = 0;
string answer;
string answer1;

namespace physics { 
        int work(int f, int x){
        return f * x; }
        
        int av_speed(int d, int t) {
        
        int av_s = (d/t);
        cout << av_s << endl; }
        
        int av_velocity(int xf, int xi, int t) {
        int base_x = xf - xi;
        int av_v = base_x/t;
        cout << av_v << endl; }
        
        int av_acceleration(int vf, int vi, int t) {
        int base_v = vf - vi;
        int av_a = base_v/t;
        cout << av_a << endl; }

        int weightf(int m, int g){
        return m * g; }
        
        int gpe(double m, double h){
            cout << "Any undefined or missing?" << endl; cout << "(1 for yes):";
            cin >> y; cout << "\n";
                if (y == 1) {
                cout << "You must have the energy then?" << endl;
                cout << "GPE: " << endl;
                int gpe1 = 0; cin >> gpe1;
                float gpe2 = gpe1/9.8;
                    //For height
                        cout << "Have you got the mass? (Yes or no)" << endl;
                        cin >> answer1;
                        if (answer1 == "yes") {
                        cout << "What is the mass: " << endl; cin >> m;
                        float gpe3 = gpe2/m;
                        cout << "The height will be: " << gpe3 << " Meters";
                        }
                    //For Mass
                        if (answer1 == "no") {
                        cout << "What is the height: " << endl; cin >> h;
                        float gpe4 = gpe2/h;
                        cout << "The mass will be: " << gpe4 << " KG"; 
                        } } 
                        else {
                        float gpe0 = m*9.8*h;
                        return gpe0; } }
                 

        int ke(int m, int v){
        v = (v)*v;
        m = (m/2);
        return m * v; }
        
        int sound_speed(int dto, int et){
        return (dto*2) * et; }
} 

using namespace physics;
//Forces
int g,f;
//Masses
int m;
//Measurable scalars
int t,d,h,et,dto;
//Displacement quantities
int xf, xi,x;
//Velocities
int vf,vi,v;  
#define WEIGHT_FORCEP "( m*g )"
#define WORKP "( f*x )"
#define AVER_VELOCITYP "( (xf - xi) / t )" 
#define AVER_SPEEDP "( d / t )"
#define AVER_ACCELERATIONP "(vf -vi) / t "
#define GRAVITATIONAL_PEP "(m*g*h)"
#define KINETIC_ENERGYP "(0.5*m*v^2)"
#define SPEED_SOUNDP "((dto*2)*et)"  
#define VARS1 "m = mass, g = acceleration due to gravity, f = force \n" 
#define VARS2 "x = displacement, t = time \n"
#define VARS3 "xf = final displacement, xi = initial displacement \n"
#define VARS4 "d = distance travelled, v = velocity, vf = final velocity \n" 
#define VARS5 "vi = initial velocity, dto = distance to object \n"
#define VARS6 "et = echo time \n" 

// MAIN
int main() {
    //Class member
    int input = 0;
    bool repeatInput = true;
    while (repeatInput) {
    cout << "*********************************" << endl;
    cout << "             Menu                " << endl;
    cout << "*********************************" << endl;
        cout << "0: Variable meanings" << endl;
        cout << "1: Work(J)" << endl;
        cout << "2: Weight force(N) (On earth)" << endl;
        cout << "3: Average velocity(ms-1)" << endl;
        cout << "4: Average Speed(ms-1)" << endl;
        cout << "5: Average Acceleration(ms-2)" << endl;
        cout << "6: Gravitational Potential Energy(J)" << endl;
        cout << "7: Kinetic Energy(J)" << endl;
        cout << "8: Speed of sound(ms-1)" << endl;
        cout << "Note: Type 1 under variable y if you have an undefined " << endl;
        cout << "Or missing variable in your formula to be solved" << endl;
        cout << "**************************" << endl;
        cin >> input;
        
        if ( input > 10 ) {
            cout << "insuficient data, please choose again" << endl;
            cin >> input;
        }
        else {
            switch (input) {
            case 0:
                cout << VARS1 << VARS2 << VARS3 << VARS4 << VARS5 << endl;
                cout << VARS6 << endl;
                break;
            case 1:
                cout << "The formula for work done is " << WORKP << endl;
                cout << "What are your variables?"<< endl;
                cout << "f: ";
                cin >> f;
                cout  << "x: ";
                cin >> x;
                cout << "The work done will be: " << physics::work(f,x); 
                cout << " Joules.";
                cout << endl;
                break;
            case 2:
                cout << "The formula for weight force is " << WEIGHT_FORCEP<< endl;
                cout << "What are your variables?"<< endl;
                cout << "m: ";
                cin >> m;
                cout << "g: ";
                cin >> g;
                cout << "The weight will be " << physics::weightf(m,g); 
                cout << " Newtons.";
                break;
            case 3:
                cout << "The formula for average velocity is";
                cout << AVER_VELOCITYP << endl;
                cout << "What are your variables?"<< endl;
                cout << "Initial displacement: ";
                cin >> xi;
                cout << "Final displacement: ";
                cin >> xf;
                cout << "time taken: ";
                cin >> t;
                cout << "The velocity will be " << physics::av_velocity(xf,xi,t);  
                cout << "ms-1 (Meters per second)" << endl;
                break;
            case 4:
                cout << "The formula for average speed is " << AVER_SPEEDP << endl;
                cout << "What are your variables?"<< endl;
                cout << "distance travelled: ";
                cin >> d;
                cout << "time taken: ";
                cin >> t;
                cout << "The average speed will be " << physics::av_speed(d,t);
                cout << "ms-1 (Meters per second)" << endl;
                break;
            case 5:
                cout << "The formula for average acceleration is ";
                cout << AVER_ACCELERATIONP << endl;
                cout << "What are your variables?"<< endl;
                cout << "Final velocity: "; cin >> vf;
                cout << "Initial Velocity: "; cin >> vi;
                cout << "time taken: "; cin >> t;
                cout << "The average acceleration will be "; 
                cout << physics::av_acceleration(vf,vi,t);
                cout << "ms-2 (meters per second per second)" << endl;
                break;
            case 6:
                cout << "The formula for gravitational potential energy is ";
                cout << GRAVITATIONAL_PEP << endl;
                cout << "What are your variables?"<< endl;
                cout << "Mass(kg): "; cin >> m;
                cout << "Height(m): "; cin >> h;
                cout << physics::gpe(m,h);
                cout << "J Is the GPE value ";
                break;
            case 7:
                cout << "The formula for kinetic energy is ";
                cout << KINETIC_ENERGYP << endl;
                cout << "What are your variables?"<< endl;
                cout << "Mass(kg)"; cin >> m;
                cout << "Velocity: "; cin >> v;
                cout << "The kinetic energy will be "; 
                cout << physics::ke(m,v);
                cout << " Joules" << endl;
                break;
            case 8:
                cout << "The formula for calculating th speed of sound is";
                cout << SPEED_SOUNDP << endl;
                cout << "What are your variables?" << endl;
                cout << "Distance to object: "; cin >> dto;
                cout << "Echo time: "; cin >> et;
                cout << physics::sound_speed(dto,et);
                cout << "ms-1 (meters per second)" << endl;
                break;
            default:
                cout << "More forumale?" << endl;
                cout << "Please email andre@the-endless-abode.dhs.org" << endl;
                cout << "To suggest or add more" << endl;
                break;
            }
        }
        cout << "\n\n";
        cout << "Is that all you want to do?" << endl;
        cout << "Yes or No" << endl;
        cout << "\n";
        cin >> answer;
        if (answer == "dennis") {
        int be = 0;
        for (be = 0;be < 1000; be++) 
        cout << "Goatse is fun" << "\n\n\n\n";
        } 
        if (answer == "yes")
            repeatInput = false;
    }
    return 0;
}