A short C++ program that uses Cantera is shown below. This program reads in a specification of a gas mixture from an input file, and then builds a new object representing the mixture. It then sets the thermodynamic state and composition of the gas mixture, and prints out a summary of its properties.

#include "cantera/core.h"
#include <iostream>

using namespace Cantera;

// The actual code is put into a function that can be called from the main program.
void simple_demo()
{
    // Create a new Solution object
    auto sol = newSolution("h2o2.yaml");
    auto gas = sol->thermo();

    // Set the thermodynamic state by specifying T (500 K) P (2 atm) and the mole
    // fractions. Note that the mole fractions do not need to sum to 1.0 - they will
    // be normalized internally. Also, the values for any unspecified species will be
    // set to zero.
    gas->setState_TPX(500.0, 2.0*OneAtm, "H2O:1.0, H2:8.0, AR:1.0");

    // Print a summary report of the state of the gas.
    std::cout << gas->report() << std::endl;
}

// The main program just calls function simple_demo within a 'try' block, and catches
// CanteraError exceptions that might be thrown.
int main()
{
    try {
        simple_demo();
    } catch (CanteraError& err) {
        std::cout << err.what() << std::endl;
        return 1;
    }
    return 0;
}

Before you can run this program, it first needs to be compiled. On a Linux system using the GCC compiler, a typical command line for compiling this program might look like this:

g++ combustor.cpp -o combustor -O3 $(pkg-config --cflags --libs cantera)

This example relies on the pkg-config tool to determine the appropriate compiler flags, such as those specifying the Cantera header and library files. For more advanced and flexible methods of compiling programs that use the Cantera C++ library, see Compiling Cantera C++ Programs.

This program produces the output below:

 ohmech:

      temperature   500 K
         pressure   2.0265e+05 Pa
          density   0.36118 kg/m^3
 mean mol. weight   7.4093 kg/kmol
  phase of matter   gas

                         1 kg             1 kmol
                    ---------------   ---------------
         enthalpy       -2.4772e+06       -1.8354e+07  J
  internal energy       -3.0382e+06       -2.2511e+07  J
          entropy             20699        1.5337e+05  J/K
   Gibbs function       -1.2827e+07       -9.5038e+07  J
heat capacity c_p            3919.1             29038  J/K
heat capacity c_v              2797             20724  J/K

                     mass frac. Y      mole frac. X     chem. pot. / RT
                    ---------------   ---------------   ---------------
               H2           0.21767               0.8           -15.644
                H                 0                 0
                O                 0                 0
               O2                 0                 0
               OH                 0                 0
              H2O           0.24314               0.1           -82.953
              HO2                 0                 0
             H2O2                 0                 0
               AR           0.53919               0.1           -20.503
               N2                 0                 0

As C++ programs go, this one is very short. It is the Cantera equivalent of the "Hello, World" program most programming textbooks begin with. But it illustrates some important points in writing Cantera C++ programs.