1. Miscellaneous Stuff Which there wasn’t enough time to cover
And this still isn’t everything…
Fall 2004
CS-183 Dr. Mark L. Hornick

2. 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 []
Fall 2004
CS-183 Dr. Mark L. Hornick

3. 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)
Fall 2004
CS-183 Dr. Mark L. Hornick

4. 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 > >
Fall 2004
CS-183 Dr. Mark L. Hornick

5. 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
Fall 2004
CS-183 Dr. Mark L. Hornick

6. 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
Fall 2004
CS-183 Dr. Mark L. Hornick

7. Algorithm Functions (2)
unique – Remove all adjacent duplicates
replace – Substitute on match
remove – Remove on match
reverse – Swap order
Fall 2004
CS-183 Dr. Mark L. Hornick

8. 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
Fall 2004
CS-183 Dr. Mark L. Hornick

9. 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
Fall 2004
CS-183 Dr. Mark L. Hornick

10. Iterator Types ++ (all) *: Assign from/to *: Rvalue/lvalue input
output
forward
bidirectional --
list<T>::iterator
random access
vector<T>::iterator
+=, -=, <, [], …
needed for algorithm’s sort
Fall 2004
CS-183 Dr. Mark L. Hornick

11. 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
Fall 2004
CS-183 Dr. Mark L. Hornick

12. For More Information
Highlight “algorithm” in MSVC, press F1, select “algorithm header file” for complete list
Fall 2004
CS-183 Dr. Mark L. Hornick