Computer Programming Lab 9

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Computer ProgrammingLab 9

• Shyh-Kang Jeng
• Department of Electrical Engineering/
• Graduate Institute of Communication Engineering
• National Taiwan University

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Lab Exercise 8 Bubble Sort Part A

• Modify the bubble sort implementation to produce
  the following output shown in next page

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Sample Output
Data items in original order 2 6 4 8 10
12 89 68 45 37 After pass 0 2 4 6 8 10
12 68 45 37 89 After pass 1 2 4 6 8 10 12 45
37 68 89 After pass 2 2 4 6 8 10 12 37 45 68
89 After pass 3 2 4 6 8 10 12 37 45 68
89 After pass 4 2 4 6 8 10 12 37 45 68
89 After pass 5 2 4 6 8 10 12 37 45 68
89 After pass 6 2 4 6 8 10 12 37 45 68
89 After pass 7 2 4 6 8 10 12 37 45 68
89 After pass 8 2 4 6 8 10 12 37 45 68
89 Data items in ascending order 2 4 6
8 10 12 37 45 68 89 Number of comparison
81
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Template (1/2)

• // CPLab9\Main.cpp
• include ltiostreamgt
• using stdcout
• using stdendl
• include ltiomanipgt
• using stdsetw
• int main()
• const int SIZE 10
• int a SIZE 2, 6, 4, 8, 10, 12, 89, 68,
  45, 37
• int hold
• int numberOfComparisons 0

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Template (2/2)

• cout ltlt "Data items in original order\n"
• for ( int i 0 i lt SIZE i )
• cout ltlt setw( 4 ) ltlt a i
• cout ltlt "\n\n"
• / Write bubble sort implementation here /
• cout ltlt "\nData items in ascending order\n"
• for ( int j 0 j lt SIZE j )
• cout ltlt setw( 4 ) ltlt a j
• cout ltlt "\nNumber of comparisons "
• ltlt numberOfComparisons ltlt endl
• return 0
• // end main

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Lab Exercise 8 Bubble Sort Part B

• After the first pass, the largest number is
  guaranteed to be in the highest-numbered element
  of the array, after the second pass, the two
  highest numbers are in place, and so on.
  Instead of making nine comparisons on every pass,
  modify the bubble sort to make eight comparisons
  on the second pass, seven on the third pass, and
  so on. The output should look like that given in
  the next page.

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Sample Output
Data items in original order 2 6 4 8 10
12 89 68 45 37 After pass 0 2 4 6 8 10
12 68 45 37 89 After pass 1 2 4 6 8 10 12 45
37 68 After pass 2 2 4 6 8 10 12 37 45 After
pass 3 2 4 6 8 10 12 37 After pass 4 2 4 6
8 10 12 After pass 5 2 4 6 8 10 After pass
6 2 4 6 8 After pass 7 2 4 6 After pass 8
2 4 Data items in ascending order 2 4 6
8 10 12 37 45 68 89 Number of comparison
45
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Lab Exercise 8 Bubble Sort Part C (1/2)

• The data in the array may already be in the
  proper order or near-proper order, so why make
  nine passes if fewer will suffice? Modify the
  bubble sort to check at the end of each pass if
  any swaps have been made. If none has been made,
  then the data must be in the proper order, so the
  program should terminate. If swaps have been
  made, then at least one more pass is needed. Do
  the following

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Lab Exercise 8 Bubble Sort Part C (2/2)

• Use the data set 2, 6, 4, 8, 10, 12, 89, 68, 45,
  37 from Parts A and B. Did the program appear
  to run any differently?
• Now use the data shown in the output given in
  next page. Did the program appear to run any
  differently?

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Sample Output
Data items in original order 6 4 2 8 10
12 37 45 68 89 After pass 0 4 2 6 8 10
12 37 45 68 89 After pass 1 2 4 6 8 10 12 37
45 68 After pass 2 2 4 6 8 10 12 37 45 Data
items in ascending order 2 4 6 8 10 12
37 45 68 89 Number of comparison 24
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Follow-Up Activity

• Remove bubble sort from main and place it in a
  function named bubbleSort that takes an array
  argument and a constant integer representing the
  arrays size. What should this function return?
  Is the array passed call-by-reference or
  call-by-value?