Bohr_Energy_Calc_A1.cpp

// Assignment 1 - calculate transition energy using simple Bohr formula

//Include headers
#include "stdafx.h"
#include<iostream>
#include<iomanip>
#include<string>
#include<vector>
#include<limits>

using namespace std;

//Define Global variables
const double electron{ 1.602e-19 };
bool y {true};

//Define Functions

//Electron volt function
double photon_energy_eV(int atomic_number, int initial_quantumNumber, int final_quantumNumber){
	double energy_diff;
	energy_diff = -13.6*pow(atomic_number,2)*((1 / pow(initial_quantumNumber,2)) - (1 / pow(final_quantumNumber,2)));
	return energy_diff;
}

//Joules function
double photon_energy_J(int atomic_number, int initial_quantumNumber, int final_quantumNumber){
	double energy_diff;
	energy_diff = -13.6*electron*pow(atomic_number, 2)*((1 / pow(initial_quantumNumber, 2)) - (1 / pow(final_quantumNumber, 2)));
	return energy_diff;
}

int main(){

	while (y){

		//declare variables
		int n_initial, n_final;
		double Energy_J;
		double Energy_eV;
		int atomic_number;

		// Ask user to enter atomic number

		cout << "Please enter the atomic number you, Z:" << endl;	
		cin >> atomic_number; cout << endl;

		//check atomic number is valid  
		
		while (cin.fail() || atomic_number > 118 || atomic_number <= 0 || cin.peek() != '\n'){
			cout << "Sorry the atomic number was not vaild!" << endl << " Remember it must be an integer within 1 and 118." << endl;
			cin.clear(); cin.ignore(numeric_limits<streamsize>::max(), '\n'); cin >> atomic_number;
		}

		// Ask user to enter initial and final quantum numbers

		cout << "Please enter your initial quantum value followed by your final quantum value:" << endl;		
		cin >> n_initial; //input initial QM state
		cin >> n_final; //input final QM state

		//test if QM # positive integer

		while (cin.fail() || n_initial <= 0 || n_final <= 0 || cin.peek() != '\n'){
			cout << "Quantum nubers need to be positive integer and non-zero" << endl << "please eneter the initial quantum state followed by the final state:" << endl;
			cin.clear(); cin.ignore(numeric_limits<streamsize>::max(), '\n');
			cin >> n_initial;
			cin >> n_final;
		}

		//test if initial QM # > final QM #

		while (n_initial < n_final || n_initial == n_final){
			cout << "Initial Quantum state must be greater than final state to emitt photon" << endl << "please eneter the initial quantum state followed by the final state" << endl;
			cin.clear(); cin.ignore(numeric_limits<streamsize>::max(), '\n');
			cin >> n_initial;
			cin >> n_final;
		}

		// ask if he want answer in eV or Joules

		while (true){
			cout << "Do you want your answer in Joules or eV?" << endl;
			string conversion;
			vector <string> poss_J{ "Joules", "joules", "J", "j", "Joule", "joule" }; //accepted Joule inputs
			vector <string> poss_eV{ "e", "eV", "EV", "ev", "electron Volts" }; //accepted eV inputs
			cin >> conversion;

			//User has selected Joules and spit out answer	
			if (std::find(poss_J.begin(), poss_J.end(), conversion) != poss_J.end()){
				Energy_J = photon_energy_J(atomic_number, n_initial, n_final);
				cout << "The photon energy of the energy transition is: " << setprecision(4) << Energy_J << " J" << endl;
				break;
			}

			//User has selected eV and display answer
			if (std::find(poss_eV.begin(), poss_eV.end(), conversion) != poss_eV.end()){
				Energy_eV = photon_energy_eV(atomic_number, n_initial, n_final);
				cout << "The photon energy of the energy transition is: " << setprecision(4) << Energy_eV << " eV" << endl;
				break;
			}

			//No valid unit selection
			else{
				cout << "You have not selected Joules or eV." << endl;
			}				
		}
		
		//repeat operation
		
		cout << "Repeat? [y/n]" << endl;
		char choice;
		cin >> choice;
		if (choice == 'n'){
			y = false;
		}
		
	}

	return 0;
}