truct base {    virtual void print() { cout << "base!"; }}struct derived: base {    virtual void print() { cout << "derived!"; }}Now, if you have an object and call the print member function, the print function of the derived is always called, because it overrides the one of the base. If the function print wasn‘t virtual, then the function in the derived wouldn‘t override the base function, but would merely hide it. Overriding can be useful if you have a function that accepts a base class, and every one that‘s derived from it:void doit(base &b) {    // and sometimes, we want to print it    b.print();}