// utility.cpp #include <iostream> #include <string> #include "utility.h" useful::useful(string s, int n) { name = s; number = n; } useful::~useful() { } string useful::get_name() const { return name; } int useful::get_number() const { return number; } void useful::enlarge() { number *= 2; } void useful::print(ostream & out) const { out << "[" << name << "/" << number << "]"; } ostream & operator<<(ostream & out, const useful & u) { u.print(out); return out; } int factorial(int n) { int f = 1; for (int i = 2; i <= n; i += 1) f *= i; return f; }