/*
 * lesson9part2.cpp
 *
 *  Created on: Nov 17, 2019
 *      Author: Braydon Medeiros
 *
 *      This program calculates the future value in a bank account based on
 *      the current amount, interest rate, and number of months it remains in
 *      the back. Input and output is done through input and output files.
 */


#include <math.h>
#include <iostream>
#include <iomanip>
#include <string>
#include <fstream>

using namespace std;

double futureValue(double presentValue, double interestRate, int months);
int read (double & presentValue, double & interestRate, int & months, ifstream & inputFile);
void display (double presentValue, double interestRate, int months, double futureValue, ifstream & outputFile);

int main()
{
	double presentValue, interestRate, valueFuture;
	int months, counter;
	string fileName;

	cout << "Enter input file name" << endl;

	cin >> fileName;

	ifstream inputFile;
	inputFile.open(fileName);

	if (!(inputFile.is_open()))
	{
		cout << "File \"" << fileName << "\" could not be opened" << endl;
		return 1;
	}

	ofstream outputFile;
	outputFile.open("output.xls");

	if (!(outputFile.is_open()))
	{
		cout << "File \"output.xls\" could not be opened" << endl;
		inputFile.close();
		return 1;
	}


	while(counter)
	{
		counter = read(presentValue, interestRate, months, inputFile);
		if (counter == 1)
		{
			valueFuture = futureValue(presentValue, interestRate, months);
			display (presentValue, interestRate, months, valueFuture, outputFile);
		}
		if (counter == 2)
		{
			cout << presentValue << " " << interestRate << " " << months << endl;
			cout << "One or more of the above values are not greater than zero" << endl;
		}
	}



	inputFile.close();
	outputFile.close();
	return 0;
}

double futureValue(double presentValue, double interestRate, int months)
{
	double futureValue;
	futureValue = presentValue * pow((interestRate + 1), months);
	return futureValue;
}

int read (double & presentValue, double & interestRate, int & months, ifstream & inputFile)
{
	cin >> presentValue >> interestRate >> months;
	interestRate = interestRate / 100;
	if(presentValue < 0 || interestRate < 0 || months < 0)
		return 2;
	if(inputFile.eof())
		return 0;
	return 1;
}

void display (double presentValue, double interestRate, int months, double futureValue, ifstream & outputFile)
{
	static bool firstRun = 1;
	if(firstRun) //Outputs a header on first run of the function and disables it after use.
		{
		outputFile << "Future Value\tPresent Value\tMonthly Interest\tMonths" << endl;
		firstRun = 0;
		}

	outputFile << presentValue << "/t" << interestRate << "/t" << months << "/t"<< futureValue << endl;
}