4. As part of requirement engineering, your team will develop a requirement model for your program.

a. Identify at least five use cases for the software. You only need to write down the names of the use cases. [5pt]

b. Draw a use case diagram that covers the main functionalities. Aside from the ones you just listed above, you also need to include a few additional use cases that you deem reasonable for the software. [10pt]

c) A critical use case for the software would be Edit .lrc file. Use an activity diagram to describe how you would define the steps of action to carry out this use case. Draw it below. [10pt] Hint: One way for a user to do so might be like this:

i) The user types in or pastes the lyrics into the editor and navigates to the beginning;

ii) The user starts playing music;

iii) When the time is right, the user clicks a button or press a key to insert the timestamp.

iv) The cursor then jumps to the head of the next line automatically.

v) The user now repeats step 3) and 4), until all the lines have been correctly labeled.

vi) The user saves the file or checks the correctness by replaying the song with the .lrc file before saving it.