#include <vector> #include <iostream> using namespace std;

int main() { vector<Gromit*> dogs;

for(int i = 0; i < 5; i++) dogs.push_back(new Gromit(i));

apply(dogs, &Gromit::speak, 1); apply(dogs, &Gromit::eat, 2.0f); apply(dogs, &Gromit::sleep, 'z', 3.0); apply(dogs, &Gromit::sit);

} ///:~

Although the definition of apply( ) is somewhat complex and not something you’d ever expect a novice to understand, its use is remarkably clean and simple, and a novice could easily use it knowing only what it is intended to accomplish, not how. This is the type of division you should strive for in all of your program components: The tough details are all isolated on the designer’s side of the wall, and users are concerned only with accomplishing their goals, and don’t see, know about, or depend on details of the underlying implementation

Template-templates

//: C03:TemplateTemplate.cpp #include <vector>

#include <iostream> #include <string> using namespace std;

//As long as things are simple,

//this approach works fine: template<typename C>

void print1(C& c) { typename C::iterator it;

for(it = c.begin(); it != c.end(); it++) cout << *it << " ";

cout << endl;

}

//Template-template argument must

//be a class; cannot use typename: template<typename T, template<typename> class C>

Chapter 15: Multiple Inheritance

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