CS 403: Programming Languages Lecture 24 Fall 2003 Department of Computer Science University of...

QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.

CS 403: Programming Languages

Lecture 24

Fall 2003

Department of Computer Science

University of Alabama

Joel Jones

Lecture 24 2


Overview Announcements

Talk today Colloquim tomorrow at 11AM in Houser 108, Jiageng Li,

University of Alabama, Integrated Authorization for Grid System Environments

Review Session next class Study Guide MP3 questions Evaluation Forms The STL from a comparative programming

language standpoint

The Computer Science Department, CS Advisory Board,

and ACM Student Chapter

present

Mike ThomasCIO, Gulf States Paper

“Computer Science in Heterogenous, Multidimensional Business

Environments”

5:00-6:00 PM, Tuesday, Dec. 2nd, EE 119

Pizza & drinks served.

Lecture 24 4


Collections

Almost all programming languages support aggregations of primitive types in some way C has structs, unions, arrays

Pair Up:

What way of aggregating does Smalltak have?

What way of aggregating does Scheme have?

Lecture 24 5


Closures and aggregation Aggregation is just a simple data type

mechanism—what else is needed to have concise powerful? A lower syntactic overhead way of specifying new

behavior that works over an aggregate data structure Smalltalk: myCollection do: [ code ] Scheme: (map myList (lambda code )) Works because the language provides a way of

specifying functions “in-place”

Lecture 24 6


C++ Templates

Parameterized data types Type-safe macros Come in two types

Class Templates Function Templates

Lecture 24 7


Class Templates

Can specialize with class (see listing #1) template <class T> class Stack… Stack<class Message>

Or any other type Stack<int>

Lecture 24 8


Class Template Member Functions

Method body must be in .h file

Lecture 24 9


Using a Class Template

See listing #2 What is the output?

Lecture 24 10


Function Templates

Specialize a function to take polymorphic arguments Template <class T> T max(T a, T b)

But be careful with pointer types… See listing #3 What does it print?

Lecture 24 11


Template Function Specialization

To fix “problem”, use type-specific version: template<> char* max(char* a, char* b){ return strcmp(a, b) > 0 ? a : b; }

Lecture 24 12


Standard Template Library (STL) Good reference at:

http://www.sgi.com/tech/stl/

Generic Programming specify algorithms and data structures that work with

any data type

Core Components Containers Algorithms Iterators

Lecture 24 13


STL: Containers Data structures that manage a set of

memory locations Doesn’t contain many member functions Creating, copying, destroying, adding,

removing No pointers to elements Algorithms do the “day-to-day” stuff

Lecture 24 14


STL: Iterators

Used to traverse elements of containers Uniform set/naming across containers Algorithms designed to work with a

particular iterator categoryRandom Access

Bi-Directional

Forward

Output Input

Lecture 24 15


STL: Algorithms Decoupled from containers Parameterized by iterator types Algorithm categories:

Non-mutating sequence operations Mutating sequence operations Searching and Sorting Set Operations Heap operations Numeric operations Miscellaneous

Lecture 24 16


Orthogonal Component Structure So how does this all work together?

vector<int> v(3);v[0] = 7;v[1] = v[0] + 3;v[2] = v[0] + v[1];reverse(v.begin(), v.end());

So what kind of components are v, v.begin(), and reverse?

Algorithm Iterator Container

Lecture 24 17


Example STL: deque Double-Ended QUEue Supports:

Random access to elements Constant time insertion & removal of elements @ end Linear time insertion and removal of elements in the middle Constant time insertion & removal of elements @ beginning

What role would the template parameter to deque fulfill?

Lecture 24 18


Example STL: deque Use:

deque<int> Q;Q.push_back(3);Q.push_front(1);Q.insert(Q.begin() + 1, 2);Q[2] = 0;copy(Q.begin(), Q.end(), ostream_iterator<int>(cout, “ “));

What does this do?

Lecture 24 19


Example STL: stack<T, Sequence>

Adaptor that supports restricted subset of Container functionality Insertion, removal, and inspection of element

at the top of the stack Does not allow iteration through its elements

Lecture 24 20


Example STL:stack<T, Sequence> Example use:

int main() { stack<int> S; S.push(8); S.push(7); S.push(4); assert(S.size() == 3); assert(S.top() == 4); S.pop(); assert(S.top() == 7); S.pop(); assert(S.top() ==8); S.pop(); assert(S.empty());}

Lecture 24 21


Containers Sequences

vector, deque, list, slist, bit_vector

Associative Containers set, map, multiset, multimap, hash_set, hash_map,

hash_multiset, hash_multimap, hash

String package char_traits, basic_string, rope (not STL)

Container adaptors stack, queue, priority_queue, bitset

Lecture 24 22


Algorithms Non-mutating algorithms

for_each, find,, count, mismatch, equal, search Mutating algorithms

copy, swap, transform, replace, fill, generate, remove, unique, reverse, rotate, random_shuffle, random_sample, partition, stable_partition, sorting, nth_element, binary search, merge, set operations heap operations, min and max, lexicographical_compare, permutations

Generalized numeric algorithms iota, accumulate, inner_product, partial_sum,

adjacent_difference, power

Lecture 24 23


Iterators Iterator classes

istream_iterator ostream_iterator front_insert_iterator back_insert_iterator insert_iterator reverse_iterator reverse_bidirectional_iterator raw_storage_iterator sequence_buffer

CS 403: Programming Languages Lecture 24 Fall 2003 Department of Computer Science University of...

Documents

Transcript of CS 403: Programming Languages Lecture 24 Fall 2003 Department of Computer Science University of...