Lab Exercise

There are two Parts to this exercise.

In the first part, you will answer questions related to the code given in Section $2.$

In the second part, you will download the functioning code and implement additional recursive functions.

Part $1$

Answer the following questions:

Although, it is not explicitly stated, what is the base case for writeSub$()?$

What is the base case for insertEndSub$()?$

If you wanted to print the list backwards, how would you modify writeSub$()?$ Why?

Part $2$

Get the files:

recursion.cpp

listrec.h

There are two files used in this program:

listrec.h contains the implementation of the linked list class

recursion.cpp $--$ the main program. This contains the calls to test the linked list member functions. Including the recursive ones.

Your primary tasks for this exercise are:

Alter the writeSub$()$ function so that it prints the list in reverse.

Steps include:

Try to run this program. You should get the prompt:

Enter a list of characters :

Now, type "abc" and enter. You will get the following output:

Enter a list of characters : abc

a b $[$c$]$

List : abc

List : abc!

a b c $[!]$

Press any key to continue

Now, modify the writeSub$()$ function $($in the listrec.h file$)$ so that it prints in reverse. Build and Run your program, you should get the following output:

Enter a list of characters : abc

a b $[$c$]$

List : cba

List : $!$cba

a b c $[!]$

Press any key to continue

Next, create a new recursive function that will insert the character $\text{'}$a$\text{'}$ immediately before each occurence of the character $\text{'}$b$\text{'}.$ The cursor will not change.

add code in the listrec.h file for aBeforeb$()$ and aBeforebSub$().$ The function prototypes exist, you have to add code to get them running.

Build and run the executable.

Your output will look like this:

Enter a list of characters : abc

a b $[$c$]$

List : cba

List : $!$cba

a a b c $[!]$

Press any key to continue

Prepare a test plan for this function that includes list containing the character $\text{'}$b$\text{'}$ at the beginning, middle, and end. A test plan form follows.

Execute your test plan. If you discover mistakes in your implementation of the aBeforeb$()$ function, correct them and execute your test plan again.

Test Plan for the aBeforeb Operation

Test Case List Expected Result Checked

b in beginning

b in middle

b at end

multiple b$\text{'}$s

When you are finished, your program should:

Insert the char $\text{'}$a$\text{'}$ before any $\text{'}$b$\text{'}$ in the input without getting stuck

If there are multiple $\text{'}$b$\text{'}$s$,$ your program must insert multiple $\text{'}$a$\text{'}$s

Your program must not drop or lose other parts of the input

An example run could look like this: