I’m having trouble with running the example interactive program from the tutorial. I simply cut and pasted it, but after it asks for “an expression involving ‘x’ “ it just hangs and never does anything. The problem seems to be in the line ‘ex e = reader(cin)’, I got the other examples to run just fine, but the reader(cin) seems to be problematic.

#include <iostream>

#include <string>

#include <stdexcept>

#include <ginac/ginac.h>

    using namespace std;

    using namespace GiNaC;

    int main()

{

        cout << "Enter an expression containing ’x’: " << flush;

        parser reader;

        try {

            ex e = reader(cin);

            symtab table = reader.get_syms();

            symbol x = table.find("x") != table.end() ?

            ex_to<symbol>(table["x"]) : symbol("x");

            cout << "The derivative of " << e << " with respect to x is ";

            cout << e.diff(x) << "." << endl;

        } catch (exception &p) {

            cerr << p.what() << endl;

}

}

Caseys-MacBook-Air:ginac casey$ g++ ginacPlay.cpp -o ginacPlay.out -lginac -lcln

Caseys-MacBook-Air:ginac casey$ ./ginacPlay.out

Enter an expression containing ’x’: x

…It just hangs there for several minutes.