Description
Learning Objectives
The primary learning objectives of this assignment include event-driven programming abstractions, creation
of graphical applications and concurrent programming abstractions including POSIX threading. Additional
learning objectives include the use of generics, containers and synchronization abstractions.
Specifications
1. Your program must find the prime numbers between two numbers which must be read from the
QLineEdit “From” and “To”, as in Figure 1. Use quint64 as your data type to allow a larger range of
prime numbers to be searched. Use QString::toULongLong to perform the conversion. The values in
“From” and “To” must be included in the search.
2. Create a menu, “File”, as a QMenu with the following actions as QActions in the QMenu, as in Figure
1, and functionality:
a. “Start” – start the prime number search
b. “Stop” – terminate the prime number search
c. “Exit” – terminate the prime number search if running and cleanly exit the application
3. Create three buttons with the same text and functionality as the above actions, as in Figure 1.
4. When the program is not searching for prime numbers the “Stop” button and action must be disabled
and the “Start” button and action must be enabled, as in Figure 1 and 2.
5. Likewise, when the program is searching for prime numbers the “Stop” button and action must be
enabled and the “Start” button and action must be disabled, as in Figure 2.
6. While the prime search is being performed a QProgressBar must be shown and it must be regularly
updated indicating how far the program has progressed through the search, as in Figure 2. This
progress bar must be visible during a search, as in Figure 2, and not visible otherwise, as in Figure
3.
7. While the prime search is being performed, as in Figure 2, and until the next search starts a label
must be shown, as in Figure 3, and it must be regularly updated indicating the number of primes
found in the specified range during the search. This label must be visible during the search, must be
visible after the search has completed with the final prime count and must not be visible before the
first prime search after the application opened, as in Figure 1.
8. As the prime numbers are found they must be listed in a QListView, as in Figure 2, which uses a
custom class which inherits from QAbstractListModel as its model. The prime numbers found must
remain in the QListView until the start of the next prime search, as in Figure 3.
9. The search must be performed in a different thread from the QApplication’s exec() call. The thread
must be created using pthreads. You may use the Sieve of Eratosthenes algorithm to test for prime
numbers.
10. When the search is terminated by the user the thread should be cancelled. Use deferred POSIX
thread cancellation. You may use pthread_testcancel to cause the thread to cancel. Implement a
cleanup routine, deallocate any memory that the thread dynamically allocated and print a message
to the terminal (e.g. via stdout). A cancellation example is posted in Scholar.
11. Make sure that the search thread does not starve the GUI of processor time or cause the GUI to be
otherwise blocked causing the interface to freeze. The progress bar, counter and the list of numbers
must be updated as the search progresses. (This is a common use for threads in GUI applications)
12. After the search is stopped, whether by a normal exit or cancellation, if the user clicks on the “Start”
button or action again then the search should start from the beginning. The QListView should be
cleared, the counter reset and the progress bar start from 0% again.
3
ECE-3574: Applied Software Engineering, Fall 2014
Homework 7
Figure 1 Figure 2
Figure 3
Notes
1. 0 and 1 are not prime but 2 is.
2. Once the user starts the search then the search itself, the displayed primes and the progress bar
must not be affected by a change of the “From” and “To” values.
3. Be sure to read the most up-to-date documentation for QListView, QAbstractListModel and
advisories in the documentation about subclassing QAbstractListModel.
