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#include <stdio.h>
#include <stdlib.h>

class A {
    public:
    virtual void saraza() = 0;
};

class B: public A {
    public:
    virtual void saraza() {
        printf("saraza");
    }
};

class C {
    public:
    void trulala(A unDato) {
        a.saraza();
    }
};

int main() {
    B b();
    C c();

    c.trulala(b);
    return 0;
}

/*
barbazul@barbazul ~/Organizacion de Datos/tpDatos/lib/File $ g++ test.cpp -o test
test.cpp:18:20: error: cannot declare parameter ‘unDato’ to be of abstract type ‘A’
test.cpp:4:7: note:   because the following virtual functions are pure within ‘A’:
test.cpp:6:18: note:    virtual void A::saraza()
test.cpp: In member function ‘void C::trulala(A)’:
test.cpp:19:9: error: ‘a’ was not declared in this scope
test.cpp: In function ‘int main()’:
test.cpp:27:7: error: request for member ‘trulala’ in ‘c’, which is of non-class type ‘C()’
*/