Laboratory Manual
EEL 3801
Lab #3
Laboratory Assignment #3
EEL 3801 Introduction to Computer Engineering
Topic: Nested looping in assembly language.
Turn in: .LST file and screen output.
Bubble Sort
Write a program using a bubble sort algorithm to sort a string in ascending order stored in the
data segment. Print out the string on the screen before and after the sort. Use a string of at least
20 characters in length and the starting string should not be in ascending order.
The implementation of the bubble sort consists of a simple double loop. The first iteration of the
inner for loop moves through the string from bottom to top, comparing adjacent characters. If the
lower indexed character's value is higher than its higher-indexed neighbor, then the two values
are swapped. Once the smallest value is encountered, this process will cause it to "bubble" up to
the top of the array. The second iteration of the inner for loop repeats this process. Since the
smallest value reached the top of the array on the first pass, there is no need to compare the top
two elements on the second pass. Likewise, each succeeding pass through the array compares
adjacent elements, looking at one less value than the preceding pass.
The bubble sort algorithm is similar to the following:
For i = 0 to string_length - 2
for j = string_length - 2 to i
if string[j] > string[j + 1] then
swap string[j] with string[j + 1];
Output:
1. Output the initial string to the screen.
2. Output the final string to the screen.
3. Output the number of passes required to sort the string.
TURN IN: .LST File and screen Output.
1
