CS240

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CS-240

• Container Classes

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Definition

• Container Class - a class that is used to hold
  collections of objects (items)
• Bounded - has a maximum number of items that can
  be held usually based on an array as the
  container
• Unbounded - no limit on number of items usually
  based on lists or trees

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STLs Container Categories

• Sequence Containers
• vector
• deque
• list
• Adapter Containers
• stack
• queue
• priority queue
• Associative Containers
• set, multiset
• map, multimap

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Vector

• Like an array
• stores elements of like type
• sequential indices but random access
• Unlike an array
• can grow larger and smaller at run time
• only at back end
• can have boundaries

V0
V1
V2
...
Vn-1
Room to grow
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Lists

• Sequential access in either direction
• add/delete from front, back and middle

front
back
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Stack

• Add (push)and delete (pop) at only one end
• Last-in-first-out (LIFO)
• operates like a pile of cafeteria trays

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Queue

• Add (enqueue) at rear and remove (dequeue) from
  front end
• First-in-first-out (FIFO)
• like a grocery store check-out line
• ordered chronologically (time of entry)

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Priority Queue

• Operates like a queue but ordering is by item
  priority rather than time of entry
• entry is always at rear but exiting is based on
  filtering of item
• like grocery store check-out but guy entering
  elbows his way up in line until he encounters a
  bigger guy

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Sets

• A collection of unique, related members
• no ordering associated with member entry
• associative operators
• membership
• union
• intersection
• Multiset
• like a set but may have duplicate members

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Maps

• Correlates (maps) keys and values
• example Java Hash table
• Doesnt store data by position
• Allows the key to index the value
• Multimap - like a map but duplicate keys are
  allowed

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STL Vector Class

• include ltvectorgt
• to allocate a vector
• of 5 ints . vectorltintgt v15
• of 10 doubles.vectorltdoublegt v210
• of 6 strings.vectorltstringgt v36
• of 8 chars, initialized with blanks.
• vectorltchargt line(80, )
• of 5 ints, initialized with zeros.
• vectorltintgt v4 (0,0,0,0,0)

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Vector Constructors

• vector( ) - creates an empty vector
• vector(int n, const T valueT()) - create a
  vector of n elements each having a specified
  value.
• Vector(T first, T last) - initialize the vector
  from the address range forst to last

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The Vector Operations

• back( ) - returns the last element in the vector
• push_back(const value) - add the item tp the
  end of the vector
• pop_back( ) - removes and returns the item at the
  back
• size( ) - returns number of elements in the
  vector
• resize(int n, const TfillT()) - modify the
  size of the vector to n elements, if n is bigger
  new elements with value fill are added at end. If
  smaller, original values are kept for the n
  elements, rest are discarded
• const T operator (int i )const - overloaded
  index operator
• empty( ) - returns true if vector is empty