Question $3(25$ Marks$)$

$3.$a

i$.$ There are two common models used for version control software. State both and explain their key differences.

$[5$ Marks$]$

ii$.$ Git internally uses one of these two models. Explain why git can be used for either approach and name an example system using git this way.

$[4$ Marks$]$

$3.$b The diagram below is a graph of a small number of commits $($the numbered circles$)$ in a git history. With reference to the numbered commits, state what operations were performed at each stage. Note that time flows from left to right in the diagram.

$[8$ Marks$]$

$3.$c Explain how a merge conflict may occur when multiple people are using a git repository. Be specific in your answer.

$[3$ Marks$]$

$3.$d Consider a program written in Java, which should take a string as input and outputs a new string rearranged to put all the characters in alphabetical order, as illustrated below:

inorder$("$helloworld$")->$ "dehllloorw"

Provide at least five equivalence partitions and their test cases to test this program.

$[5$ Marks$]$

$[$Total $25$ Marks$]$