Have to make a game, help?

Hello, we are a group the had a task of making a game in matlab. It is supposed to have two players, both players start at 0. The game starts with matlab wholenumber between 1000 and 10000 that are saved in a variable S. The players are then supposed to chose a positive number in turn. S is updated and gets a new value every time a player makes a choice. When a player chooses the integer x then g (x) −f (x, S) must be added to this player's score. Every time a score is updated, the program should tell players about the new score. The program should set S equal to x/2^g(x) and inform the players about the new value of S. The game ends when S is equal to 1

Now i've done some parts, but i suck at matlab and having 4 exams to read to so if someone could give me some pointer and maybe an example on how to continue i would be so gratefull!

The main code i have so far is:

player1=0;
player2=0;
S=R();
run R.m
disp(S);
while true
    x = input('Enter a number: ', 's');
    x = str2double(x);
    if ~isnan(x)
        break;
    else
        disp('Only numbers supported');
    end
end
player1=player1 + g(x)-f(x,S);
fprintf('\n Thank you \n \n spiller1:');
disp(spiller1)

the R.m:

function [out] = R()
out = randi([1000,10000]);
end 

the f(x):

function [z]=f(x,y)
z=abs(x-y);
end

and the g(x)

function [y]=g(x)
i=0;
while true
   if (mod(x,2)==0)
       i=i+1;
       x=(x/2);
   else 
       break
   end
 
end
y=i;
end