math/polynomial-read.cpp

Example of polynom read from user input.

See also

Multivariate polynomials

* $ ./examples/math/polynomial-read               
* Type any multi-variate polynomial, then press return.
* Examples: xyz^3-4yz, (x+y+z)*(x-y-z)^2.
* (x-3)^2 + (y-2)^2 - 4
* Ok : ((9 + -4 X_1 + 1 X_1^2) + -6 X_0 + 1 X_0^2)
* 

 
#include <iostream>
#include <iomanip>
#include <sstream>
#include "DGtal/base/Common.h"
#include "DGtal/math/MPolynomial.h"
#include "DGtal/io/readers/MPolynomialReader.h"
 
using namespace std;
using namespace DGtal;
 
 
// Standard services - public :
 
int main( int /*argc*/, char** /*argv*/ )
{
  typedef double Ring;
  MPolynomial<3,Ring,std::allocator<Ring> > P;
  MPolynomialReader<3,Ring> reader;
  string str;
 
  std::cout << "Type any multi-variate polynomial, then press return." << std::endl
            << "Examples: xyz^3-4yz, (x+y+z)*(x-y-z)^2." << std::endl;
  do {
    getline( cin, str );
    if ( cin.good() && ( ! str.empty() ) )
      {
        std::string::const_iterator iter 
          = reader.read( P, str.begin(), str.end() );
        bool ok = iter == str.end();
        if ( ! ok )
          {
            std::cerr << "ERROR: I read only <" 
                      << str.substr( 0, iter - str.begin() )
                      << ">, and I built P=" << P << std::endl;
          }
        std::cout << (ok ? "Ok : " : "Err: ") << P << std::endl;
      }
  } while ( ! str.empty() );
  return 0;
}
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