Unable to access all the related predicates of a Prolog file from C++..

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C++

I am trying to access all the related predicates of a prolog file from C++. I have the prolog file as,

";new_gryffindor.pl"

sits_right_of(parvati,lavender).
sits_right_of(lavender,neville).
sits_right_of(neville,alicia).
sits_right_of(alicia,fred).
sits_right_of(fred,george).
sits_right_of(george,lee).
sits_right_of(lee,dennis).
sits_right_of(dennis,dean).
sits_right_of(dean,ginny).
sits_right_of(ginny,angelina).
sits_right_of(angelina,seamus).
sits_right_of(seamus,colin).
sits_right_of(colin,harry).
sits_right_of(harry,hermoine).
sits_right_of(hermoine,ron).
sits_right_of(ron,natalie).
sits_right_of(natalie,katie).
sits_right_of(katie,parvati).

sits_left_of(X,Y) :- sits_right_of(Y,X).

are_neighbours_of(X,Y,Z) :- sits_left_of(X,Z),
                            sits_right_of(Y,Z).

next_to_each_other(X,Y) :- sits_left_of(X,Y);
                           sits_right_of(X,Y).

And I have integrated C++ and Prolog file with the C++ code,

term_t a = PL_new_term_ref();
term_t b = PL_new_term_ref();
term_t ans = PL_new_term_ref();
PL_put_variable(ans);

predicate_t p_consult = PL_predicate("consult", 1, "database");
term_t t = PL_new_term_ref();
PL_put_string_chars(t, "new_gryffindor.pl");
PL_call_predicate(NULL, 0, p_consult, t);

fun = PL_new_functor(PL_new_atom("sits_right_of"),2);
PL_cons_functor(ans, fun, a, b);

char *fact1;
char *fact2;
if(PL_call(ans, NULL)) {
    PL_get_atom_chars(a, &fact1);

    PL_get_atom_chars(b, &fact2);
    cout << fact1 << " sits right of " << fact2; 
}

This C++ Code is giving me the result for the very first predicate of "sits_right_of" ,i.e, as "parvati sits right of lavender". But I want to print all the related predicates of "sits_right_of" in C++ like the prolog which gives next similar predicate's values by using semicolon ";".

sits_right_of(X,Y).
X = parvati,
Y = lavender ;
X = lavender,
Y = neville ;
X = neville,
Y = alicia ;
X = alicia,
Y = fred ;
X = fred,
Y = george ;
X = george,
Y = lee ;
X = lee,
Y = dennis ;
X = dennis,
Y = dean ;
X = dean,
Y = ginny ;
X = ginny,
Y = angelina ;
X = angelina,
Y = seamus ;
X = seamus,
Y = colin ;
X = colin,
Y = harry ;
X = harry,
Y = hermoine ;
X = hermoine,
Y = ron ;
X = ron,
Y = natalie ;
X = natalie,
Y = katie ;
X = katie,
Y = parvati.

What I have tried:

I tried looping statements in C++ but it is printing the same output for multiple times..

So please help me out to print the values of other similar predicates of prolog file in C++.