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Instructions

You start your first day at an Australian company called "Doctor Data", which specializes in information recovery. You aced your job interview through your knowledge of C++ and von Neumann probes. As you have seen a lot of test files, your new boss wants you to recreate the respective source and header files from some test code the company has recently recovered.

In this exercise, you are going to recreate lost files. Currently the content of the files is unusable garbage data.

The workflow of this concept exercise is very similar to the structure of Exercism's practice exercises.
The exercise introduction text is only one part of the specification.
The test file is your definitive guide to solving a given problem.
Due to the way C++ compilation works, the test results might not show up in the web interface until you have implemented a minimal version of every class, function and enumeration that is required by the tests.
If you receive compilation errors, they might disappear once you have addressed all tasks and tests.

You have four tasks, all related to recovering the lost code in the header and source files.

1. Try to extract some first clues

You look at two recovered lines from the test files:

heaven::Vessel bob{"Robert Johansson", 1};
heaven::Vessel will{"Riker", 2, star_map::System::BetaHydri};

Your sharp eye instantly recognized a namespace heaven. You also see that there must be a class called Vessel. The constructor can apparently be called with two or three arguments. The first argument seems to be of type string, the second one is a number. It is possible to initialize the Vessel class with a third argument. The third argument comes from a star_map namespace. It is an enumerator of type System. You even got one of the enumerations: BetaHydri.

Prepare the source and header files with your discovered information. You need two namespaces: heaven and star_map. The heaven namespace has a class Vessel, which can be called with two or three arguments. The System enum is to be placed in the star_map namespace and has an BetaHydri enumeration. Keep an eye out for other enumerations, so that you can constantly update the System enum.

2. Find more details

You uncover more lines from the test:

heaven::Vessel bob{"Robert Johansson", 1};
REQUIRE(bob.current_system == star_map::System::Sol);
REQUIRE(bob.generation == 1);
heaven::Vessel bob5 = bob.replicate("Mario");
REQUIRE(bob5.current_system == star_map::System::Sol);
REQUIRE(bob5.generation == 2);

The newly found test lines uncover another member function of the Vessel class: replicate. This function receives a string and returns another Vessel instance. You get an idea about the default value of the third argument of the constructor from the previous task. You also see two public member variables of the Vessel class and the specification of the replicate member function.

Add the replicate function and the public member variables current_system and generation to the header and source files.

3. Look into the inner workings

You find some more interesting lines in the recovered test files:

heaven::Vessel bob6{"Homer", 3, star_map::System::EpsilonEridani};
REQUIRE(bob6.busters == 0);
bob6.make_buster();
REQUIRE(bob6.busters == 1);
bool success = bob6.shoot_buster();
REQUIRE(success);
REQUIRE(bob6.busters == 0);
success = bob6.shoot_buster();
REQUIRE_FALSE(success);

Apparently, the Vessel class has a member variable busters, that can be changed with the two class member functions make_buster and shoot_buster. Until other information surfaces, you take a guess that the make_buster function returns void. As there is a test for the return value of shoot_buster, you assume that the function returns a bool.

Add the two functions and the member variable to the Vessel class. Keep looking for other System enumerators.

4. Complete the picture

During your scan of the test files you find only two uncovered sections of the code:

heaven::Vessel bob1{"Bob", 1, star_map::System::AlphaCentauri};
heaven::Vessel marv{"Marvin", 2, star_map::System::DeltaEridani};
heaven::Vessel milo{"Milo", 3, star_map::System::DeltaEridani};
heaven::Vessel howie{"Howard", 4, star_map::System::Omicron2Eridani};

REQUIRE("Bob" == heaven::get_older_bob(bob1, marv));
REQUIRE(heaven::in_the_same_system(marv, milo));
REQUIRE_FALSE(heaven::in_the_same_system(marv, howie));

You see two functions, that are not members of the Vessel class, as they are not called with an instance. get_older_bob compares two Vesselinstances and returns a string. in_the_same_system compares two Vesselinstances and returns a bool.

Implement the last missing functions from the recovered lines above.