Miscellaneous Stuff

Miscellaneous Stuff • Which there wasn’t enough time to cover • And this still isn’t everything… CS-183Dr. Mark L. Hornick

Managing newed pointers (1) • Wouldn’t it be nice if newed memory were released when pointer went out of scope? • The auto_ptr (auto pointer) class from the standard library does this. • An object “owns” the pointer and calls delete when destroyed (destructor) • But not delete [] CS-183Dr. Mark L. Hornick

Managing newed pointers (2) #include <memory> // auto_ptr ... void f() { ... auto_ptr<MyClass> apObject(new MyClass(...)); apObject->function(...); ... } // no delete (apObject's dtor// takes care of it) CS-183Dr. Mark L. Hornick

Managing newed pointers (3) • Containers of objects (vector<MyClass>) only hold a single object type • Polymorphism: use virtual functions and pointers to hold any derived type (vector<MyBaseClass*>) • Must delete each object before losing its pointer • Add auto_ptr‘s “auto delete” feature… • vector< auto_ptr< MyBaseClass > > CS-183Dr. Mark L. Hornick

Algorithm Library • About 50 methods for containers and other objects • Makes extensive use of templates • Access #include <algorithm> using std::…; • Limitations • Places restrictions on some objects CS-183Dr. Mark L. Hornick

Algorithm Functions (1) • find – Match value, if not found return last • Uses operator== • find_if – Match using generic exp • count – How many matches? (operator==) • count_if – Count matching generic exp • partial_sum – sum of 1st through Nth element CS-183Dr. Mark L. Hornick

Algorithm Functions (2) • unique – Remove all adjacent duplicates • replace – Substitute on match • remove – Remove on match • reverse – Swap order CS-183Dr. Mark L. Hornick

Other Container Functions • random_shuffle – Requires indexing • merge – Two sorted sequences • sort – Sort a sequence • Uses operator < • Requires indexing (random access) • list<> has its own version CS-183Dr. Mark L. Hornick

Non-Container Functions • min – smallest of two • max – largest of two • swap – switch values between two objects • iter_swap – same, but do the swap given iterators CS-183Dr. Mark L. Hornick

forward bidirectional random access Iterator Types ++ (all) *: Assign from/to *: Rvalue/lvalue input output list<T>::iterator -- vector<T>::iterator +=, -=, <, [], … needed for algorithm’s sort CS-183Dr. Mark L. Hornick

for_each • Does the same thing to all objects in a sequence • May not modify objects • Requires a function that has a single parameter • Data type in the container cell void printSquare(TYPE in); for_each(li.begin(), li.end(), printSquare); // func. Name CS-183Dr. Mark L. Hornick

For More Information • Highlight “algorithm” in MSVC, press F1, select “algorithm header file” for complete list CS-183Dr. Mark L. Hornick

Miscellaneous Stuff