//---------------------------------------------------------------------------
/*
QuadraticSolver, solver of quadratic equations
Copyright (C) 2008 Richel Bilderbeek
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//---------------------------------------------------------------------------
// From http://www.richelbilderbeek.nl/CppQuadraticSolver.htm
//---------------------------------------------------------------------------
#include <iostream>
#include <sstream>
#include <cassert>
#include <vector>
#include <cmath>
#include <string>
#include <iterator>
//Gives harmless warnings when you work with the Borland compiler
//BCC32.EXE version 6.0.10.157. When a more recent compiler is
//used, the warning will probably not occur anymore.
#pragma warn -8041
#include <boost/lexical_cast.hpp>
#pragma warn +8041
#pragma hdrstop
//---------------------------------------------------------------------------
#pragma argsused
//---------------------------------------------------------------------------
void ShowLicence()
{
std::cout
<< "QuadraticSolver, solver of quadratic equations" << std::endl
<< "Copyright (C) 2008 Richel Bilderbeek" << std::endl
<< std::endl
<< "This program is free software: you can redistribute it and/or modify" << std::endl
<< "it under the terms of the GNU General Public License as published by" << std::endl
<< "the Free Software Foundation, either version 3 of the License, or" << std::endl
<< "(at your option) any later version." << std::endl
<< std::endl
<< "This program is distributed in the hope that it will be useful," << std::endl
<< "but WITHOUT ANY WARRANTY without even the implied warranty of" << std::endl
<< "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the" << std::endl
<< "GNU General Public License for more details." << std::endl
<< "You should have received a copy of the GNU General Public License" << std::endl
<< "along with this program. If not, see <http://www.gnu.org/licenses/>." << std::endl
<< std::endl
<< "Programmed at the 12th July of 2008 by Richel Bilderbeek" << std::endl
<< "From http://www.richelbilderbeek.nl" << std::endl
<< std::endl
<< std::endl;
}
//---------------------------------------------------------------------------
//From http://www.richelbilderbeek.nl/CppSolveQuadratic.htm
const std::vector<double> SolveQuadratic(const double a, const double b, const double c)
{
if (a == 0.0)
{
if (b == 0.0)
return std::vector<double>(1,0.0);
else
return std::vector<double>(1,c/b);
}
const double d = (b * b) - (4.0 * a * c);
if (d < 0.0)
return std::vector<double>();
if (d == 0.0)
return std::vector<double>(1,-b/(2.0*a));
const double rD = std::sqrt(d);
std::vector<double> solutions;
solutions.reserve(2);
solutions.push_back((-b + rD)/(2.0 * a));
solutions.push_back((-b - rD)/(2.0 * a));
return solutions;
}
//---------------------------------------------------------------------------
//From http://www.richelbilderbeek.nl/CppAskUserForString.htm
const std::string AskUserForString()
{
std::string s;
std::getline(std::cin,s);
return s;
}
//---------------------------------------------------------------------------
//From http://www.richelbilderbeek.nl/CppIsDouble.htm
const bool IsDouble(const std::string& s)
{
std::istringstream i(s);
double temp;
return ( (i >> temp) ? true : false );
}
//---------------------------------------------------------------------------
//From http://www.richelbilderbeek.nl/CppAskUserForDouble.htm
const double AskUserForDouble()
{
while (1)
{
const std::string s = AskUserForString();
if (IsDouble(s)==false) continue;
return boost::lexical_cast<double>(s);
}
}
//---------------------------------------------------------------------------
int main()
{
ShowLicence();
while (1)
{
std::cout << "Please enter a value for a" << std::endl;
const double a = AskUserForDouble();
std::cout << "Please enter a value for b" << std::endl;
const double b = AskUserForDouble();
std::cout << "Please enter a value for c" << std::endl;
const double c = AskUserForDouble();
std::cout << "Solutions of this quadratic equations are:" << std::endl;
const std::vector<double> v = SolveQuadratic(a,b,c);
std::copy(v.begin(),v.end(),std::ostream_iterator<double>(std::cout," "));
if (v.empty()==true)
std::cout << "None..." << std::endl;
else
std::cout << std::endl;
std::cout << "Type 'q' to quit, anything else to continue." << std::endl;
const std::string quit = AskUserForString();
if (quit == "q" || quit == "Q") break;
}
ShowLicence();
}
//---------------------------------------------------------------------------
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