calling virtual function from within another virtual function

Hi Guys,
 Is Ok to invoke a virutal function from within virtual function.
Specifically here is the example I tried and it seems to have worked:
(what I am doing is derived class::foo() (foo is virtual)invokes base
case implementation of foo(), which in turn calls bar() thats virutal
too . So I am reusing some part of logic which is common to both base
and derived and overriding other part which is different by using 2
virtual functions like this)

#include <iostream.h>
using namespace std;

class C {
public:
  virtual void foo(int foo) {
    cout << "in C::foo() foo=" << foo << endl;
    bar(foo);
  }

  virtual void bar(int bar) {
    cout << "in C::bar() bar=" << bar << endl;
  }
private:
  int i;
};

class A : public C {
public:
  virtual void foo(int foo) {
    cout << "in A::foo() foo=" << foo << endl;
    if(foo > 0)
      C::foo(foo);
  }

  virtual void bar(int bar) {
    cout << "in A::bar() bar=" << bar << endl;
  }

};

int main()
{
  C c;
  A a;

  c.foo(10);
  a.foo(20);

  C* tmp;
  tmp = &c;
  tmp->foo(30);
  tmp = &a;
  tmp->foo(40);
}

output:
in C::foo() foo=10
in C::bar() bar=10

in A::foo() foo
in C::foo() foo
in A::bar() bar

in C::foo() foo=30
in C::bar() bar=30

in A::foo() foo=40
in C::foo() foo=40
in A::bar() bar=40

so is it OK to use polymorphism like this from point of view of C++
standard? I tried this with SUN CC compiler on a solaris box. Are
there any potential downsides to following this paradigm, if so what
would be better way of doing this?
Thanks,
Sunil

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