1. Chapter 10: Applications of Arrays and the class vector
C++ Programming: From Problem Analysis to Program Design, Fifth Edition
Chapter 10: Applications of Arrays and the class vector

2. Objectives In this chapter, you will:
Explore how to sort an array using the bubble sort, selection sort, and insertion sort algorithms
Learn how to implement the binary search algorithm
Become familiar with the vector type
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

3. List Processing List: a collection of values of the same type
Basic list operations:
Search the list for a given item
Sort the list
Insert an item in the list
Delete an item from the list
Print the list
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

4. Searching Sequential search algorithm
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

5. Searching (cont'd.) List with 1000 elements
Search item is the second item
Sequential search makes two key comparisons
Search item is the 900th item
Sequential search makes 900 key comparisons
Search item is not in the list
Sequential search makes 1000 key comparisons
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

6. Searching (cont'd.) Sequential search
Not very efficient for large lists
On average, number of key comparisons equal to half the size of the list
Does not assume that the list is sorted
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

7. Bubble Sort list[0]...list[n - 1]
List of n elements, indexed 0 to n - 1
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

8. Bubble Sort (cont'd.) Series of n - 1 iterations
Successive elements list[index] and list[index + 1] of list are compared
If list[index] > list[index + 1]
Elements list[index] and list[index + 1] are swapped
Smaller elements move toward the top
Larger elements move toward the bottom
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

9. Bubble Sort (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

10. Bubble Sort (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

11. Bubble Sort (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

12. Bubble Sort (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

13. Bubble Sort (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

14. Bubble Sort (cont'd.) List of length n n = 1000
Exactly n(n - 1) / 2 key comparisons
On average n(n - 1) / 4 item assignments
n = 1000
500,000 key comparisons
250,000 item assignments
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

15. Selection Sort
Rearrange the list by selecting an element in the list and moving it to its proper position
Finds the location of the smallest element in the unsorted portion of the list
Moves it to the top of the unsorted portion of the list
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

16. Selection Sort (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

17. Selection Sort (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

18. Selection Sort (cont'd.)
In the unsorted portion of the list:
Find the location of the smallest element
Move the smallest element to the beginning of the unsorted list
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

19. Selection Sort (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

20. Selection Sort (cont'd.)
List of length n
Exactly n(n - 1) / 2 key comparisons
3(n - 1) item assignments
n = 1000
500,000 key comparisons
3000 item assignments
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

21. Insertion Sort
Sorts the list by moving each element to its proper place
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

22. Insertion Sort (cont'd.)
Consider the element list[4]
First element of unsorted list
list[4] < list[3]
Move list[4] to proper location
At list[2]
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

23. Insertion Sort (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

24. Insertion Sort (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

25. Insertion Sort (cont'd.)
During the sorting phase
Array containing the list is divided into two sublists: sorted and unsorted
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

26. Insertion Sort (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

27. Insertion Sort (cont'd.)
List of length n
About (n2 + 3n – 4) / 4 key comparisons
About n(n – 1) / 4 item assignments
n = 1000
250,000 key comparisons
250,000 item assignments
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

28. Binary Search Much faster than a sequential search List must be sorted
“Divide and conquer”
Compare search item with middle element
Less than middle: search only upper half of list
More than middle: search only lower half of list
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

29. Binary Search (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

30. Binary Search (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

31. Binary Search (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

32. Performance of Binary Search
L is a sorted list of size 1024
Every iteration of the while loop cuts the size of the search list by half
At most, 11 iterations to determine whether x is in L
Binary search will make 22 comparisons at most
L has elements
Binary search makes 42 item comparisons at most
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

33. Performance of Binary Search (cont'd.)
List of length n
Maximum number comparisons 2log2n + 2
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

34. vector type (class)
Only a fixed number of elements can be stored in an array
Inserting and removing elements causes shifting
vector type implements a list
vector container
vector
vector object
object
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

35. vector type (class) (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

36. vector type (class) (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

37. vector type (class) (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

38. vector type (class) (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

39. Programming Example: Election Results
Presidential election for the student council of your local university
Write a program to analyze the data and report the winner
Four major divisions labeled as Region 1, Region 2, Region 3, and Region 4
Each division has several department
Each department manages its own voting process and directly reports the results to the election committee
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

40. Programming Example: Election Results (cont'd.)
Voting is reported in the following form:
Desired output:
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

41. Programming Example: Election Results (cont'd.)
Assume that six candidates are running
Program can be modified to accommodate any number of candidates
Data is provided in two files:
candData.txt consists of the names of candidates
voteData.txt each line consists of voting results
One entry per line
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

42. Programming Example: Input and Output
Input: Two files, one containing the candidates’ names and the other containing the voting data
Output: election results in a tabular form and the winner
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

43. Programming Example: Problem Analysis
Program must organize the voting data by region
Program must calculate total number of votes received by each candidate as well as the total votes cast in the election
Names of the candidates must appear in alphabetical order
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

44. Programming Example: Problem Analysis (cont'd.)
Data type of a candidate’s name and number of votes are different
Separate arrays
Use a two-dimensional array to hold the next four columns of the output
One-dimensional array to hold the total votes received by each candidate
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

45. Programming Example: Problem Analysis (cont'd.)
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

46. Programming Example: Algorithm Design
Read the candidates’ names into the array candidatesName
Sort the array candidatesName
Initialize the arrays votesByRegion and totalVotes
Process the voting data
Calculate the total votes received by each candidate
Output the results
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

47. Programming Example: Function getCandidatesName()
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

48. Programming Example: Function sortCandidateName()
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

49. Programming Example: Function initialize()
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

50. Programming Example: Process Voting Data
Get a candidateName, regionNumber, and numberOfVotesForTheCandidate
Find the row number in the array candidatesName that corresponds to this candidate
This gives the corresponding row number in the array votesByRegion for this candidate
Find the column in the array votesByRegion that corresponds to the regionNumber
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

51. Programming Example: Process Voting Data (cont'd.)
Update the appropriate entry in the array votesByRegion by adding the numberOfVotesForTheCandidate
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

52. Programming Example: Function binSearch()
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

53. Programming Example: Function processVotes()
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

54. Programming Example: Function addRegionsVote()
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

55. Programming Example: Function printHeading()
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

56. Programming Example: Function printResults()
Initialize sumVotes, largestVotes, and winLoc to 0
For each row in each array:
Output the final lines of output
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

57. Programming Example: Main Algorithm
Declare the variables
Open the input file candData.txt
If the input file does not exist, exit the program
Read the data from the file candData.txt into the array candidatesName
Sort the array candidatesName
Close the file candData.txt and clear the input stream
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

58. Programming Example: Main Algorithm (cont'd.)
Open the input file voteData.txt
If the input file does not exist, exit the program
Initialize the arrays votesByRegion and totalVotes
Process the voting data and store the results in the array votesByRegion
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

59. Programming Example: Main Algorithm (cont'd.)
Calculate the number of total votes received by each candidate and store the results in the array totalVotes
Print the heading
Print the results
C++ Programming: From Problem Analysis to Program Design, Fifth Edition

60. Summary List Sorting algorithms Binary search vector type
Set of elements of the same type
Sorting algorithms
Bubble sort
Selection sort
Insertion sort
Binary search
Compare performance to sequential search
vector type
C++ Programming: From Problem Analysis to Program Design, Fifth Edition