With virtual member functions:
#include <iostream>
struct X {
virtual void f() { std::cout << "X::f()\n"; }
};
struct Y : X {// Specifying virtual again here is optional // because it can be inferred from X::f(). virtual void f() { std::cout << “Y::f()\n”; }
};
void call(X& a) {
a.f();
}
int main() {X x; Y y; call(x); // outputs “X::f()” call(y); // outputs “Y::f()”
}Without virtual member functions:
#include <iostream>
struct X {
void f() { std::cout << "X::f()\n"; }
};
struct Y : X {
void f() { std::cout << "Y::f()\n"; }
};
void call(X& a) {
a.f();
}
int main() {X x; Y y; call(x); // outputs “X::f()” call(y); // outputs “X::f()”
}