CSE 14 Lecture Notes - Lecture 14: Bubble Sort
CMPS12A Lecture 14 – Sorting and Searching through Arrays
There are many ways of finding values in an array that are entered by the user. Loops must be
implemented in order to iterate through the arrays and functions make your life easier when
dealing with these methods. Values in an array can also be sorted in any order that you want it
to, given the correct algorithm for it. Here in BubbleSort, the method swaps values from least
value to greatest.
Example:
class BubbleSort {
public static void main(String[] args) {
double [] A = {7.0, 6.0, 5.0, -2.0, 2.3, 8.4, -1.5}
sort(A);
for (int i = 0; i<A.length; i++) {
Syste.out.pritA[i] + “ “;
System.out.println();
}
static void sort(double [] a) {
int i, n;
for (n = a.length; n>1; n--) {
for (i=0; i<n-1; i++) {
if (a[i] > a[i+1])
swap(a, i, i+1);
}
}
}
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static void swap(double [] a, int i, int j) {
double temp = a[i];
a[i] = a[j];
a[j] = temp;
}
}
The only thing with this sort is that the values in the array are only swapped through one
iteration of the array. Thus, the whole array would not be from least to greatest; bubblesort
basically just switches the current index from the next one, then goes to the next index and
switches the current one with the next one, and so on till the last index, ONLY if the current one
is greater than the next one. If one wanted to change the whole array from least to greatest,
you would need to call on the sort function many times until you get the desired result.
Here is a picture of how it would look like:
To find a given target in an array, you would want to do a Sequential Search, iterating through
the array until it finds the target, thus giving you the index where the target was found.
static int SeqSearch(int[] a, int t) {
for (int i = 0; i<a.length; i++) {
if (a[i] == t)
return i;
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