-TAs and office hours announced Updates -TAs and office hours announced -DRC students: can take quizzes after class (quizzes will remain open for 1 hour after class) (Please email me)

-When using git for homework and projects, make sure it’s PRIVATE Updates -When using git for homework and projects, make sure it’s PRIVATE

Data Structures data object set or collection of instances integer = {0, +1, -1, +2, -2, +3, -3, …} daysOfWeek = {S,M,T,W,Th,F,Sa} Any set or collection is a data object. Set = a collection of distinct objects

Data Object instances may or may not be related myDataObject = {apple, chair, 2, 5.2, red, green, Jack} The instances of integer and daysOfWeek are related. In the former, all instances are whole numbers, whereas in the latter all instances name days of the week. The instances of myDataObject don’t seem to be related.

Data Structure Data object + Among instances of integer 369 < 370 relationships that exist among instances and elements that comprise an instance Among instances of integer 369 < 370 280 + 4 = 284 You can have ordering relationships –2 before –1 before 0 before 1 etc (relational operators such as <, >, =, etc). Elements could be related by operations such as add, subtract, etc.

Data Structure Among elements that comprise an instance 369 3 is more significant than 6 3 is immediately to the left of 6 9 is immediately to the right of 6

add, subtract, predecessor, multiply Data Structure The relationships are usually specified by specifying operations on one or more instances. add, subtract, predecessor, multiply

Linear (or Ordered) Lists An abstract data type (implementation varies) instances are of the form (e0, e1, e2, …, en-1) where ei denotes a list element n >= 0 is finite list size is n Set {e0, e1, e2} is the same as Set {e1, e0, e2} but Linear List (e0, e1, e2) is different from Linear List (e1, e0, e2)

Linear Lists L = (e0, e1, e2, e3, …, en-1) relationships e0 is the zero’th (or front) element en-1 is the last element ei immediately precedes ei+1 A data object is a set of instances; an instance of a linear list is an ordered set of elements.

Linear List Examples/Instances Students in COP3530 = (Jack, Jill, Abe, Henry, Mary, …, Judy) Exams in COP3530 = (exam1, exam2, exam3) Days of Week = (S, M, T, W, Th, F, Sa) Months = (Jan, Feb, Mar, Apr, …, Nov, Dec) Size of Students in COP3530 is 240, Exams is 3, DOW is 7, and Months is 12. Notice that Days of Week is used as an example of both a data object and of a linear list. As a data object, {S, M, T, …} and {M, W, S, …} describe the same data object with 7 allowable instances S, M, T, … As a linear list (S, M, T, …) and (M, W, S, …) are two different instances of a linear list. Linear List itself may be viewed as data object, which is simply the set of all possible linear list instances.

Linear List Operations—size() determine list size L = (a,b,c,d,e) size = 5

Linear List Operations—get(theIndex) get element with given index L = (a,b,c,d,e) get(0) = a get(2) = c get(4) = e get(-1) = error get(9) = error

Linear List Operations—indexOf(theElement) determine the index of an element L = (a,b,d,b,a) indexOf(d) = 2 indexOf(a) = 0 indexOf(z) = -1 The index of a nonexistent element is defined to be –1. When theElement is in the list an index between 0 and size()-1 is the result. So –1 would be an invalid index and is used to represent the case when theElement is not in the list

Linear List Operations—remove/erase(theIndex) Remove/delete element with given index L = (a,b,c,d,e,f,g) erase(2) removes c and L becomes (a,b,d,e,f,g) index of d,e,f, and g decrease by 1

Linear List Operations—remove/erase(theIndex) Remove/delete element with given index L = (a,b,c,d,e,f,g) remove(-1) => error remove(20) => error

Linear List Operations—insert(theIndex, theElement) add an element so that the new element has a specified index L = (a,b,c,d,e,f,g) insert(0,h) => L = (h,a,b,c,d,e,f,g) index of a,b,c,d,e,f, and g increase by 1

Linear List Operations—insert(theIndex, theElement) L = (a,b,c,d,e,f,g) insert(2,h) => L = (a,b,h,c,d,e,f,g) index of c,d,e,f, and g increase by 1 add(10,h) => error add(-6,h) => error

Data Structure Specification Language independent Abstract Data Type C++ Abstract Class

Linear List Abstract Data Type AbstractDataType LinearList { instances ordered finite collections of zero or more elements operations empty(): return true iff the list is empty, false otherwise size(): return the list size (i.e., number of elements in the list) get(index): return the indexth element of the list indexO f(x): return the index of the first occurrence of x in the list, return -1 if x is not in the list erase(index): remove the indexth element, elements with higher index have their index reduced by 1 insert(theIndex, x): insert x as the indexth element, elements with theIndex >= index have their index increased by 1 output(): output the list elements from left to right }

Linear List As An Abstract Class An abstract class may include constants, variables, abstract methods, and nonabstract methods.

Linear List As C++ Abstract Class template<class T> class linearList { public: virtual ~linearList() {}; virtual bool empty() const = 0; virtual int size() const = 0; virtual T& get(int theIndex) const = 0; virtual int indexOf(const T& theElement)const = 0; virtual void erase(int theIndex) = 0; virtual void insert(int theIndex, const T& theElement) = 0; virtual void output(ostream& out) const = 0; };

Extending A C++ Class template<class T> class arrayList : public linearList<T> { // code for all abstract methods of linearList must come here } If arrayList does not provide an implementation for all abstract methods of linearList, arrayList also is abstract and so cannot be instantiated.

To-do Git: C++: http://www.sbf5.com/~cduan/technical/git/ http://git-scm.com/book/en/v2 C++: http://www.cplusplus.com/doc/tutorial/templates/