examples/tutorial/complx.cpp

/**************************************************************************
 *
 * complx.cpp - Complex Number example program.
 *
 * $Id: //stdlib/dev/examples/stdlib/tutorial/complx.cpp#11 $
 *
 ***************************************************************************
 *
 * Copyright (c) 1994-2005 Quovadx,  Inc., acting through its  Rogue Wave
 * Software division. Licensed under the Apache License, Version 2.0 (the
 * "License");  you may  not use this file except  in compliance with the
 * License.    You    may   obtain   a   copy   of    the   License    at
 * http://www.apache.org/licenses/LICENSE-2.0.    Unless   required    by
 * applicable law  or agreed to  in writing,  software  distributed under
 * the License is distributed on an "AS IS" BASIS,  WITHOUT WARRANTIES OR
 * CONDITIONS OF  ANY KIND, either  express or implied.  See  the License
 * for the specific language governing permissions  and limitations under
 * the License.
 * 
 **************************************************************************/

#include <complex>
#include <utility>
#include <iostream>
    
#include <examples.h>

typedef std::complex<double> dcomplex;

// Return roots of a quadratic equation.
std::pair<dcomplex, dcomplex>
quadratic (dcomplex a, dcomplex b, dcomplex c) {

    dcomplex root = std::sqrt(b * b - 4.0 * a * c);
    a = a * 2.0;
    return std::make_pair ((-b + root) / a, (-b - root) / a);
}


int main () {
    
    dcomplex a(2, 3);
    dcomplex b(4, 5);
    dcomplex c(6, 7);
    
    std::pair<dcomplex, dcomplex> ans = quadratic(a, b, c);

    std::cout << "Roots are " << ans.first << " and "
              << ans.second   << std::endl;

    return 0;
}