#include <iostream>
#include <iomanip>
//#include "PraticeLib.h"
using namespace std;


void WhatTheProgramWillDo()
{
	cout << "Program to solve quadratic equation: ax^2 + bx + c = 0";
}
double GetToleranceValue()
{
	double toler;
	cout << "\n\nEnter a positive tolerance value: " << flush;
	cin >> toler;
	while (toler <= 0.0)
	{
		cout << "\n*****ERROR"
			<< "\nPlease enter in a positive tolerance value: " << flush;
		cin >> toler;
	}
	return toler;
}
int GetNumberOfDecimalPlaces()
{
	int ndec;
	cout << "Enter the desired number of decimal places: " << flush;
	cin >> ndec;
	while (ndec <= 0)
	{
		cout << "\n*****ERROR"
			<< "\nPlease enter in a positive value for number of decimals: " << flush;
		cin >> ndec;
	}
	cout << fixed << setprecision(ndec);
	return ndec;
}
double GetValuesFor_a_b_c(double &a, double &b, double &c)
{
	cout << "\nEnter coefficients for a, b, and c "
		<< "\n(where \"a\" is a non-zero number): " << flush;
	cin >> a >> b >> c;
	while (a == 0.0)
	{
		cout << "\n*****ERROR"
			<< "\nPlease enter in a non-zero number for \"a\""
			<< "\n(make sure you're solving for a quadratic problem): " << flush;
		cin >> a >> b >> c;
	}
	//discrm = b*b - 4.0f * a*c;
	return (b*b - 4.0*a*c);
}
int SolveQuadraticEquation(double &a, double &b, double &c/*, double &value1, double &value2*/)
{
	//int solutionType;
	int ndec;
	double discrm, toler, realDblRt, xReal, imagr, value1, value2;
	toler = GetToleranceValue();
	ndec = GetNumberOfDecimalPlaces();
	discrm = GetValuesFor_a_b_c(a, b, c);

	if (discrm >= toler)
	{
		value1 = (-b + sqrt(discrm)) / (2 * a);
		value2 = (-b - sqrt(discrm)) / (2 * a);
		return 1;
	}
	else if (discrm > -toler)
	{
		realDblRt = -b / (2 * a);
		value1 = realDblRt;
		return 0;
	}
	else
	{
		xReal = -b / (2 * a);
		imagr = (sqrt(abs(discrm))) / (abs(2 * a));
		value1 = xReal;
		value2 = imagr;
		return -1;
	}
	//return solutionType;
}
void WriteQuadraticEquationSolution(int &solutionType, double &value1, double &value2)
{
	double a, b, c, discrm;
	solutionType = SolveQuadraticEquation(a, b, c);
	discrm = b*b - 4.0*a*c;
	if (solutionType == 1)
	{
		value1 = (-b + sqrt(discrm)) / (2 * a);
		value2 = (-b - sqrt(discrm)) / (2 * a);
		cout << "\n\nThe equation has two real roots: \n"
			<< "\n        x1 = " << value1
			<< "\n        x2 = " << value2;
	}
	else if (solutionType == 0)
	{
		value1 = -b / (2 * a);
		cout << "\n\nThe equation has one double real root: \n"
			<< "\n        " << value1;
	}
	else /*if (solutionType == -1)*/
	{
		value1 = -b / (2 * a);
		value2 = (sqrt(abs(discrm))) / (abs(2 * a));
		cout << "\n\nThe equation has two complex roots: \n"
			<< "\n        c1 = " << value1 << " + " << value2 << "i"
			<< "\n        c2 = " << value1 << " - " << value2 << "i";
	}
}
bool DoYouWantToSolveAnotherQuadraticEquation()
{
	bool solveAnother;
	cout << "\n\nDo you want to find the roots of another quadratic?"
		<< "\nEnter 0 for no, or non-zero for yes: " << flush;
	cin >> solveAnother;
	if (solveAnother == 0)
		solveAnother = false;
	else
		solveAnother = true;
	return solveAnother;
}

int main()
{
	double /*a, b, c, */value1, value2;
	int solutionType, solveAnother;

	do{
		WhatTheProgramWillDo();
		//GetToleranceValue();
		//GetNumberOfDecimalPlaces();
		//GetValuesFor_a_b_c(a, b, c);
		//SolveQuadraticEquation(a, b, c);
		WriteQuadraticEquationSolution(solutionType, value1, value2);
		DoYouWantToSolveAnotherQuadraticEquation();
	} while (solveAnother = true);

	cin.get();
	cin.get();
	return 0;
}