jsreq
Requirements
The JavaScript program implements a simple game that consists of three stages, setup, play and
end. During the play stage the game proceeds in rounds. The game is played on a grid with 10 x
10 cells. It involves a submarine that is controlled by the user and a couple of robotic killer
submarines that are controlled by the computer (that is, your program). The user and your program
are the two players of the game. All submarines can move around on the grid, but while the robotic
killer submarines are fueled by nuclear power that never runs out, the user’s submarine only has a
limited amount of fuel and needs to collect fuel cells to keep going. The robotic killer submarines
hunt the user’s submarine; the user’s submarine tries to avoid getting caught while also collecting
all the fuel cells on the grid.
The game always starts in the setup stage. During that stage the user is shown the grid and can
place three different types of objects on the cells of the grid:
by clicking on a cell and typing a number between 1 and 9, a fuel cell is placed on a grid cell, the
number indicates the amount of fuel in the fuel cell;
by clicking on a cell and typing the letter “o”, an obstacle is placed on a cell;
by clicking on a cell and typing the letter “u”, the user’s submarine is placed on a cell.
by clicking on a cell and typing the letter “k”, a robotic killer submarine is placed on a cell.
There is no limit on the number of fuel cells, obstacles and robotic killer submarines, but there is
obviously only one user’s submarine. No grid cell can contain more than one object and once an
object has been placed on a cell it cannot be changed. If the user tries to change the object placed
on a grid cell, then an error message should be shown. If the user types a character that is not
among 1 to 9, “o”, “u” and “k”, an error message should be shown.
In addition to the grid, the user must have a means to end the setup stage of the game, for
example, via a button. If the user tries to end the setup stage of the game without placing his own
submarine, then an error message should be shown and the user remains in the setup stage.
Otherwise the game continues with the play stage.
At the start and during the play stage, the user is again shown the grid, initially with all the objects
that have been placed on the grid during the setup stage, plus additional status information: The
rounds played so far, the number of units of fuel available to the user’s submarine, the user’s
score, the computer’s score. Initially, zero rounds have been played, the user’s submarine has 10
units of fuel, the user’s and the computer’s score are both zero. In addition, there must be the
possibility for the user to end the play stage at any time, for example, via a button.
While in the play stage, the game proceeds in rounds, each round starting with the user’s turn
followed by the computer’s turn. At the start of a round, the number of rounds played is increased
by one, and the information shown to the user is updated.
During his/her turn, if the number of units of fuel of the user’s submarine is zero at the start of the
turn, then the user’s submarine cannot move, a message should be shown indicating that the
submarine is out of fuel and the user’s turn then ends.
If the number of units of fuel of the user’s submarine is greater than zero at the start of the turn, the
user can attempt to move his/her submarine horizontally or vertically on the grid by typing one of
four letters:
“a” attempts to move the user’s submarine one grid cell to the left,
“d” attempts to move the user’s submarine one grid cell to the right,
“w” attempts to move the user’s submarine one grid cell up,
“x” attempts to move the user’s submarine one grid cell down.
If the user types any other character, then an error message should be shown and the user has the
possibility to type another character. If the attempted move would result in the user’s submarine
ending up outside the grid or on a cell occupied by an obstacle, then an error message should be
shown, the attempt to move fails, the user’s submarine does not move, the number of units of fuel
available to the user’s submarine does not change, and the user’s turn is over. Otherwise, the
attempted move is successful, the user’s submarine changes cells, and the number of units of fuel
available to the user’s submarine reduces by one. If the user’s submarine ends up on a grid cell
that contains a fuel cell, then that fuel cell is removed from the grid, the value V of the fuel cell is
added both to the user’s score and to the number of units of fuel available to the user’s submarine,
and the status information is updated. If the user’s submarine ends up on a cell occupied by a
robotic killer submarine, then the user’s submarine is destroyed, and the game proceeds to the end
stage.
During the computer’s turn your program attempts to move each of the robotic killer submarines in
an order that allows each to move if at all possible. Unlike the user’s submarine, the robotic killer
submarines are not only able to move horizontally and vertically but also diagonally. Just like the
user’s submarine, each robotic killer submarine only moves at most one cell in a turn. If the user’s
submarine is in a grid cell immediately surrounding a robotic killer submarine, then that robotic
killer submarine must move to the cell occupied by the user’s submarine, the user’s submarine is
destroyed, the computer’s score increases by 100, the status information is updated, and the game
proceeds to the end stage. If the user’s submarine is not in a grid cell immediately surrounding a
robotic killer submarine, but one or more of those grid cells contains a fuel cell, then the robotic
killer submarine must move to one of those fuel cells, the fuel cell is removed from the grid
(thereby the computer deprives the user of fuel), the value V of the fuel cell is added to the
computer’s score, and the status information is updated. If none of the surrounding grid cells
contains the user’s submarine nor a fuel cell, then a robotic killer submarine can move to an
arbitrary surrounding cell provided that this move does not take it to a grid cell that is outside the
grid or occupied by an obstacle or by another robotic killer submarine. A robotic killer submarine is
not allowed to stand still if it can move. However, if a robotic killer submarine cannot move at all,
then the computer should simply proceed to the next robotic killer submarine. Once an attempt has
been made to move each of the robotic killer submarines, the computer’s turn and the current
round ends, and the status information is updated.
The play stage ends if one of the following conditions becomes true
the user ends the play stage (by pressing the button provided for that);
the user’s submarine is destroyed;
there are no fuel cells left on the grid;
neither the user’s submarine nor any of the robotic killer submarines is able to move.
Once the play stage has ended, the game is in the end stage. In the end stage the program
determines the outcome of the game. The outcome is a win for the user if there are no robotic killer
submarines left on the grid or the user’s score is higher than the computer’s score; the outcome is
a win for the computer if the user’s submarine has been destroyed or the computer’s score is
higher than the user’s score; otherwise, the outcome is a draw. The program should display a
message indicating the outcome of the game and then stop. During the end stage the program
should not react to any user input or actions.
Additional requirements and comments:
It is possible that during the setup stage the user does not place any fuel cells on the grid. On
entering the play stage your program should recognise that, immediately proceed to the end stage,
and declare the outcome of the game.
It is also possible that during the setup stage the user does not place any robotic killer submarines
on the grid. On entering the play stage your program should recognise that, immediately proceed
to the end stage, and declare the outcome of the game.
You should carefully analyse in which situations the user’s submarine and the robotic killer
submarines might not be able to move in order to correctly end the play stage in such situations.
Ideally your program would move the robotic killer submarines in such a way that they increase
their chances of destroying the user’s submarine. This could be done by each robotic killer
submarine trying to decrease the distance to the user’s submarine with each move. But you could
also implement a strategy by which the robotic killer submarines try to `encircle’ the user’s
submarine in order to increase their chances. They could also `guard’ one specific fuel cell,
knowing that the user must eventually try to collect it.
Ideally your program would allow the size of the grid to be changed easily (by the maintainer of the
system), independently for each dimension.
JavaScript engines differ from browser to browser. You should make sure that your system works
in all commonly used browsers (e.g., Google Chrome, Mozilla Firefox, Microsoft Internet Explorer 9
or higher) and on all commonly used platforms (e.g., Linux derivatives and Microsoft Windows).
Your JavaScript program should only depend on your own code. JavaScript libraries/frameworks
should not be used.
Your code should be properly commented. This includes pointing out which parts of your code
have been developed with the help of on-line sources or textbooks by including references for
these sources at the appropriate points.
A script that deals satisfactorily with these additional requirements and comments, in addition to
providing the basic functionality required, will receive higher marks.