Data Abstraction and Problem Solving with C++ Walls and Mirrors by Frank M. Carrano
Text Home Text Errata	example235.cpp Go to the documentation of this file. #include <list> #include <iostream> #include <string> #include <new> using namespace std; // define a list of pointer strings typedef list<string*, allocator<string*> > STRING_PTR; namespace std { // override the default behavior of sort template<> struct greater<string*> { // override operator() to create a function object bool operator() (string* s1, string *s2) { return (*s1) > (*s2); } // end operator() }; // end std::greater } // end std namespace int main() { // create a list of pointer strings and a list iterator STRING_PTR groceryList; STRING_PTR::iterator i; // create pointers to strings in a random order // insert the string pointers to the end of the list try { string* str = new string ("apples"); groceryList.insert(groceryList.end(), str); str = new string ("bread"); groceryList.insert(groceryList.end(), str); str = new string ("juice"); groceryList.insert(groceryList.end(), str); str = new string ("carrots"); groceryList.insert(groceryList.end(), str); cout << "Number of items on my grocery list: " << groceryList.size() << endl; // sort with the overridden function object groceryList.sort(greater<string*>()); // print out the list of strings cout << "Items after the predicate sort are:" << endl; i = groceryList.begin(); while (i != groceryList.end()) { cout << (*(*i)).c_str() << endl; i++; } // end while } // end try catch (bad_alloc e) { cout << e.what() << endl; } // end catch } // end main

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