1. Today’s Learning Objective
Standard Template Library
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2. Standard Template Library
Recall array and linkedlist structures
Standard Template Library (STL)
Includes libraries for all such data structures
Each data structure in STL contains
Containers: Like data structures
Iterators: Like pointers
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3. Containers Container classes in STL Each has own iterator
Each is template class with parameter for particular data type to be stored
e.g., Lists of int
Each has own iterator
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4. Different Containers Sequential Associative
1st element, next element, … to last element
Examples: vector, linked list
Associative
Example: set and map
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5. Iterators Generalization of a pointer
Typically even implemented with pointer
Designed to hide details of implementation
Provide uniform interface across different container classes
Each container class has "own" iterator type
Similar to how each data type has own pointer type
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6. Manipulating Iterators
overloaded operators:
++, --, ==, != *
So if p is iterator variable, *p gives access to data pointed to by p
Vector container
has members begin() and end() c.begin(); //Returns iterator for 1st item in c c.end(); //Returns "test" value for end
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7. Cycling with Iterators
Cycling ability (c is a container; p is a iterator):
for (p=c.begin(); p!=c.end(); p++)
{ //process *p //*p is current data item }
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8. Vector Container: Iterator: Difference between vector and array
vector<int> container;
Iterator:
vector<int>::iterator p;
Difference between vector and array
Array size is fixed, while vector size is flexible
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9. Example: Iterators Used with a Vector (1 of 2)
#include <iostream>
#include <vector>
using namespace std;
int main( ) {
vector<int> container;
for (int i = 1; i <= 4; i++)
container.push_back(i);
cout << "Here is what is in the container:\n";
vector<int>::iterator p;
for (p = container.begin( ); p != container.end( ); p++)
cout << *p << " ";
cout << endl;

10. Example: Iterators Used with a Vector (2 of 2)
cout << "Setting entries to 0:\n";
for (p = container.begin( ); p != container.end( ); p++)
*p = 0;
cout << "Container now contains:\n";
for (p = container.begin( ); p !=container.end( ); p++)
cout << *p << " ";
cout << endl;
return 0; }
Here is what is in the container:
Setting entries to 0:
Container now contains:

11. Random Access of vector iterators
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12. List Container: Iterator: Difference between vector and list
list<int> container;
Iterator:
list<int>::iterator p;
Difference between vector and list
Vector allows random access while list do not allow
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13. Display 19.4 Two Kinds of Lists
STL list is a double link list
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14. Using the list Container(1 of 2)
#include <iostream>
#include <list>
using namespace std;
int main( ) {
list<int> LO;
for (int i = 1; i <= 3; i++)
LO.push_back(i);
LO.push_front(i); }
cout << "List contains:\n";
list<int>::iterator iter;
for (iter = LO.begin(); iter != LO.end(); iter++)
cout << *iter << " ";
cout << endl;

15. Using the list Container(2 of 2)
cout << "Setting all entries to 0:\n";
for (iter = LO.begin(); iter != LO.end(); iter++)
*iter = 0;
cout << "List now contains:\n";
cout << *iter << " ";
cout << endl;
return 0; }
List contains:
Setting all entries to 0:
List now contains:

16. Set Container Stores elements without repetition
1st insertion places element in set
Each element value is its own key
Capabilities:
Add elements
Delete elements
Ask if element is in set
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17. Set Container example (1)
#include <iostream> #include <set> using namespace std; int main() { set<char> s; set<char>::iterator p; s.insert('A'); s.insert('D'); s.insert('C'); s.insert('B');
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18. Set Container example(2)
cout << “The set contains:\n"; for (p=s.begin(); p!=s.end();p++) cout << *p << "\t"; cout << endl; s.erase('C'); cout << “The Set contains:\n"; { } return 1;
The set contains:
A B C D
Removing C:
The Set contains
A B D
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19. map Template Class Stores pairs of data <key type, value type>
Examples:
<SSN, Student GPA>
<Course Number, Course Name>
The first data (key type) is its key
Capabilities:
Add elements
Delete elements
Ask if element is in map
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