Description

PP Task 4.2 Repetition, repetition, repetition

Overview

Purpose:
Task: Learn how to use conditional and iterative control flow statements in a program.
Use the instructions on the following pages to complete the implementation of a typing practice program, and trace some small examples of iterative control flow. Submit to MyLO when complete.
Learning Outcomes: 1 @ 3 ‘
Time: Aim to complete this task before the start of Week 5.
Resources: • Introductory Programming Notes:
0 08 Making Decisions
0 09 Repeating Actions with Loops o Appendix: Code Tracing Problems
Online Mini-lectures:
Making Decisions:
Boolean expressions & comparing values
Two-way branching with if and if-else
Multi-way branching with switch o Repeating Actions with Loops:
Loop components, while and do-while
The for-loop and loop debugging tips o Code Tracing: Selection & Repetition
Submission Details
Upload the following to the MyLO submission folder for this task:
Tracing tables for the code samples at the start. This can be either photos/scans of hand-written tables (recommended) or a Word/PDF document
Your TypingTutor.java source file (no need for program screenshots in this task)
Assessment Criteria
A Completed submission will:
Include valid tracing tables for the code samples in the warm up exercise, showing the execution order and output produced Include completed implementations of the printHeading and runTutoria1 methods
Demonstrate the use of for and while loops, as appropriate to the task
Require the user to practice a different word than in the starter code
Follow the unit’s coding style for layout, variable names (use of case), and commenting (including your name at the top)
Instructions

Warm up exercise: Trace code involving repetition
1 . Create tracing tables for the following code samples. The tracing tables should illustrate the execution path each program took, both by the sequence of row numbers in the table and the output messages produced. Remember to include your name and the name of the task in the document(s) you submit.
Repetition Sample 1:
1int counter – 5
2System. out. print1n(“Message 0”
3while (counter < 8) {
4System . out . print “Message
5counter = counter + 1
6
7System. out. print1n(“Message 2”
Repetition
1
2
3
4
5 Sample 2:
int counter – 9
System. out. print1n(“Message 0” while (counter < 8) {
System . out . print “Message counter = counter + 1
6
7 System. out. print1n(“Message 2”
Repetition Sample 3:
1int counter – 10
2System. out. print1n(“Message 0”
3while (counter < 12 ) {
4counter – counter + 2
5System. out. print1n(“Message 1”
6counter – counter 1
7
8System. out. print1n(“Message 2”
Implement a program involving repetition and selection
2. Download and extract the 4.2PP Repetition Starter Code from MyLO.
3. Open TypingTutor.java in DrJava and read through the code. Although there’s a lot to take in the program can be summarised as follows:
Declare:
constants for the word to practice and required number of repetitions; variables to record the start and end time of a practice, and total time in seconds; a variable to record the number of attempts
Display the program’ s title using the printHeading() method Give instructions to the user
Perform the test by calling runTutoria1() method and
Report on the outcome of the test
Display a goodbye message using the printHeading() method
4. If you compile and run the program now you’ll find it doesn’t do much. No heading is actually displayed and the user never gets to practice typing anything (although they do appear to be very fast at doing nothing). You need to provide the implementations of printHeading() and runTutoria1().
Implement printHeading
5. Read the header comment for printHeading(), which formats its String-valued parameter to be all upper case with an underline produced by tildes near the Esc key) and a trailing blank line. To illustrate its expected behaviour, if it were called with the String “s0Me HeAdiNg” then it should display:
SOME HEADING

(Note the blank line after the heading, which must appear in your program’s output.)
6. Implement printHeading according to the following algorithm:
Method: printHeading(String heading)
Parameters :
String heading, the heading to format and display
Steps:
1 Display heading in upper case
2 For i is 0 to heading. length() 1 (i . e . , while i < heading. Length())
2-1 Display a single without ending the line
3 End the line
4 Display a blank line
TIP• : Strings have a toUpperCase() method that returns a copy of the String in capital letters.
Tip: There is a variant of System . out. println() that takes no arguments and merely prints a newline, which ends the current line of text or produces a blank line if it was already at the start of a new line of output.
7. Compile and test the program. Are you getting the opening and ending headings now?
Implement runTutoriaI
8. The runTutoria1 method continuously prompts the user to type in a particular word until they have correctly typed it the required number of times. If they never get it right then the method will never end (and that’s OK).
To illustrate its expected behaviour here is a sample interaction with the user if runTutoria1 were called with a Scanner object to read keyboard input, word equal to “Fred” and required equal to 3 (user input is highlighted)
Type ‘ Fred ‘ : Correct ! Fred
Type ‘ Fred ‘ :
Try again -Fred
Type ‘ Fred ‘ : Correct ! Fred
Type ‘ Fred ‘ :
Try again derf
Type ‘ Fred ‘ : Fred
Correct !
9. There’s currently a minimal implementation of the method, which declares one of the required variables and returns its value at the end. Complete the implementation of runTutoria1 according to the following algorithm:
Method: int runTutoria1(Scanner sc, String word, int required)
Returns :
int, the total number of attempts made by the user
Parameters :
Scanner in, to read user ‘s input
String word, the word the user must type correctly int required, the number of times they must type it correctly
Variables:
int attempts, the total number of attempts made by the user, initially 0 int correct, the number of correct entries so far, initially 0 String attempt, the current word entered by the user
Steps:
1 While correct < mustSoLve do
1-1Prompt user with “Type + word +
1-2Assign attempt value of next String from in (the Scanner)
1-3Increment attempts (add 1 to value of attempts)
1-4If attempt is equal to word then
1-4-1Display “Correct! I’
1-4-2Increment correct (add 1 to value of correct)
1-5Else
1-5-1Display “Try again”
2 Return attempts
10. When you think it’s working, modify the word the user has to type, which is defined in main().
Without showing them your code (i.e., drag the interactions pane up to hide it) have another student try your program.
1 1 . Ensure you’ve completed the code tracing exercises from the start and then upload the code traces and your completed source file to the submission folder for this task.