1. CS148 Introduction to Programming II
Ayman Abdel-Hamid
Department of Computer Science
Old Dominion University
Lecture 7:2/7/2003
Lecture 7: 2/7/2003
CS148 Spring 2003

2. Outline Sorting techniques Bubble Sort Selection Sort
Lecture 7: 2/7/2003
CS148 Spring 2003

3. Bubble Sort
Each iteration, move the next largest item into correct position. Compare each pair of Consecutive elements moving largest element up
void BubbleSort(int narray[],int length) {
for (int i = 1; i < length; i++)
//bubble up max{narray[0..n-i]}
for (int j = 0; j < length-i ; j++)
if (narray[j] > narray[j+1])
SwapArrayElements (narray[j], narray[j+1]); }
Lecture 7: 2/7/2003
CS148 Spring 2003

4. Selection Sort 1/2
(length-1) iterations where length is the array size
Each iteration selecting the largest element narray[j] and swapping it with the element that is in the position where narray[j] should be
1st iteration: select largest of all elements and swap with narray[length-1]
2nd iteration: select largest of remaining unsorted elements narray[0 .. length-2] and swap with narray[length-2] ..
Lecture 7: 2/7/2003
CS148 Spring 2003

5. Selection Sort 2/2 void SelectionSort(int narray[],int length) {
for (int i = 1 ; i < length ; i++)
//select narray[k] = max { narray[0], narray[1], ..., narray[n-i]
int k = 0;
for (int j = 1; j <= length-i; j++)
if (narray[j] > narray[k])
k =j;
SwapArrayElements(narray[k], narray[length-i]); }
Lecture 7: 2/7/2003
CS148 Spring 2003