Introduction to Standard Template Library (STL)
23
1 Introduction to Standard Template Library (STL) Wenguang Wang and Yanping Zhao March 20, 2000
description
Introduction to Standard Template Library (STL). Wenguang Wang and Yanping Zhao March 20, 2000. What Is STL?. A new C++ Library, ANSI standard Support complex data structures Vector (array), list, string, hash, set, map, queue, stack, priority queue... Support various algorithms - PowerPoint PPT Presentation
Transcript of Introduction to Standard Template Library (STL)
1
Introduction toStandard Template Library (STL)
Wenguang Wang and Yanping Zhao
March 20, 2000
2
What Is STL?
• A new C++ Library, ANSI standard• Support complex data structures
– Vector (array), list, string, hash, set, map, queue, stack, priority queue...
• Support various algorithms– Searching, sorting, heap, merging,
copying, transforming…
3
Why STL was developed?
• Some basic data structures are used everyday in your programs
• Programming them from the scratch is time consuming and error-prone
• Most of operations on these structures can be standardized
4
Why we use STL?
• More reliable and efficient implementations
• Automatic memory management• Constructing complex data
structures easily• Saving programming time and
efforts
5
Where are STL and resources?• GNU g++ on skorpio, ultra*…• Visual C++• Wenguang Wang’s home page
– http://www.cs.usask.ca/grads/wew036/stl
• Standard Template Library Programmer’s Guide– http://www.sgi.com/Technology/STL/
6
Fundamental Elements in STL?• Containers (data structures)
– vector dynamic size– list doubly linked list– string, hash
• Algorithms – sorting, heap manipulation
• Iterators (pointers)– A bridge to connect algorithms and
containers– Example
7
How to Use STL? (example)• On Unix
– GNU g++ 2.7.0 and later version
• On Windows– Visual C++ 5.0 and later version– not fully supported even in Visual C++
6.0• no hash table• no rope• more?
• Example
8
Why I am here?• I learned STL two weeks ago• I never heard of STL before• After a five minutes STL tour, I can
use it !• I found that STL helped me a lot in
programming• I want to share it with you
9
Vector -- Advantages
• Data type– basic type: integer, double, pointer, …– user-defined structures and classes
• Dynamic size
10
int *array = malloc(size*sizeof(int));//allocate
int *temp = realloc(array, new_size*sizeof(int));if (temp) array = temp; //reallocate
free(array); // deallocate
Estimate
#define SIZE 2000
Count
Count = 0;while(not end) count++;
How to get the size of the array?
vector<int> vec;vec.push_back(i);
11
Vector -- Operations
• Property operations– [ ] , size, empty
• Iterator operations– begin, end
• Manipulation operations– push_back, pop_back, insert, erase
00 1 2 3 4 5 6 7
size=8
begin endv[3]
12
#include <vector>#include <iostream>
typedef vector<int> VecInt;void main(){ VecInt vInt; VecInt::iterator it; vInt.push_back(0); vInt.push_back(1); for (it=vInt.begin(); it!=vInt.end(); it++) cout << *it << endl; for (int i=0; i<vInt.size(); i++) cout << vInt[i] << endl; it = vInt.insert(vInt.begin(), 2); vInt.erase(it);}
13
List -- Operations• Property operations
– size, empty– back, front
• Iterator operations– begin, end
• Manipulation operations– push_back, pop_back, push_front,
pop_front– insert, erase
14
#include <list>#include <iostream>typedef list<int> ListInt;void main(){ ListInt lInt; ListInt::iterator it; // stack lInt.push_front(0); lInt.push_front(1); cout << lInt.front() << endl; lInt.pop_front(); lInt.pop_front(); // queue lInt.push_back(2); lInt.push_back(3); cout << lInt.front() << endl; lInt.pop_front(); lInt.pop_front(); // iterator for (it=lInt.begin(); it!=lInt.end(); it++) cout << *it << endl;}
15
Algorithm -- Heap
• Data structure: vector or C++ array
• make_heap
• pop_heap
• push_heap
4 1 7 5 3 6 8 9
9 5 8 4 3 6 7 1
8 5 7 4 3 6 1 9
9 8 7 5 3 6 1 4
16
#include <vector>#include <algorithm>#include <iostream>typedef vector<int> VecInt;void main(){ VecInt vInt(4); int i; vInt[0]=7; vInt[1]=4; vInt[2]=9; vInt[3]=1; make_heap(vInt.begin(), vInt.end()); vInt.push_back(3); push_heap(vInt.begin(), vInt.end()); pop_heap(vInt.begin(), vInt.end()); cout << vInt.back() << endl; vInt.pop_back();}
17
User-defined Data Type
struct Event {
long timestamp;
int type;
};
typedef Event* PEvent;
typedef vector<Event> VecEvent;
typedef list<PEvent> ListPEvent;
18
User-defined Data Type (cont.)class Page {
int page_num;
int modify_flag;
int reference_cnt;
};
typedef list<Page> ListPage;
typedef ListPage* PListPage;
typedef vector<PListPage> VecPListPage;
What is the structure of VecPListPage?
page
page
page
page
page
page
19
Iterator
• Similar to pointer– *it
• Iterator for list (bidirectional iterator)– ++it, it++, --it, it--
• Iterator for vector (random access iterator)– ++it, it++, --it, it--– it+n, itBegin-itEnd
20
More details in:http://www.cs.usask.ca/grads/wew036/stl
21
22
#include <vector>#include <algorithm>void main(void){ vector<int> vInt; vector<int>::iterator begin, end; begin = vInt.begin(); end = vInt.end(); sort(begin, end);}
23
#include <iostream> //not iostream.h!#include <cstdio>#include <cstdlib>#include <vector>#include <list>#include <set>#include <map>#include <string>#include <algorithm>#ifdef _MSC_VER // for Visual C++
using namespace std;#endif
