We Continue Our Data Structure Journey!

So far we have seen:

• Singly linked lists
  • O(1) for insert, O(n) for remove.
  • A few special cases in insert and remove.
• Doubly linked lists
  • O(1) insert and remove.
  • But we have many special cases.
• Circular doubly linked list with sentinel
  • O(1) insert and remove.
  • No special cases: the code is very clean.

Lets try a list of students by grade

Operations

• Insert a new student and score.
• Remove a student.
• Update a student's score.
• Print all scores.
• Print one student's score.
• Load names and scores from a file.
• Save names and scores to a file.

See Demo sentinelDLLstream.h

Some things to note are:

• element::print takes an ostream by reference.
  • ostream can be cout, cerr, or any output file.
• Overloaded list::print, one version takes an ostream, other assumes cout.

See Demo sentinelDLLstream.cpp

Some things to note are:

• element::print uses ostream.
• list::print without ostream calls list::print with cout.
• list::print with ostream just uses stream name in place of cout.

See Demo Scores.cpp

• Many member functions use the list member functions.
• Can run with the debugger and view the array as an array and open up the contents of each linked list in the array.

Abstract Data Types

Abstarct data types are data structures that are defined by their instructions. The users of the ADT's need not and should not know how they are implemented, though it is ok to have a "mental model" of how they work. For instance:

	Stack
	Operations:
	  push
	  pop
	  isEmpty
	  print

• ADT.h - stack
• ADTsentinelDLL.h
• ADTsentinelDLL.cpp
  • Added firstOf() and getCurrentString()
• ADT.cpp - stack
• stackTest.cpp