function intcode(a)
%TODO - SPLIT INTO MORE FUNCTIONS

nparam = [3 3 1 1 2 2 3 3]; %number of parameters for opcode number "index"
param = zeros(1,max(nparam)); %THIS STORES THE ADDRESS OF THE PARAMATER, NOT THE VALUE
i=1; %pointer to start of a instruction

while(a(i) ~=99)
    %fprintf('index : %d\n',i);
    inst = str2double(regexp(num2str(a(i)),'\d','match'));
    if size(inst,2) > 1
        opcode = inst(end-1)*10 + inst(end);
    else
        opcode = inst(end);
        inst = [0, inst(end)];
    end
    inst = [ zeros(1,max(nparam) - size(inst,2) + 2 ) inst]; %pad extra zeros. find better solution
    inst(end-1:end) = [];
    inst = fliplr(inst);


    for j = 1:nparam(opcode)
        if inst(j) == 0
            param(j) = a(i+j) + 1;
        else
        param(j) = i+j;
        end
    end


    switch (opcode)
        case 1
            a(param(3)) = a(param(1)) + a(param(2));
            i = i+4;
        case 2
            a(param(3)) = a(param(1)) * a(param(2));
            i=i+4;
        case 3
            a(param(1)) = input("enter input");
            i=i+2;
        case 4
            fprintf('%d \n',a(param(1)));
            i=i+2;
        case 5
            if a(param(1)) ~= 0
                i = a(param(2)) + 1;
            else
                i = i+3;
            end
        case 6
            if a(param(1)) == 0
                i = a(param(2)) + 1;
            else
                i = i+3;
            end
        case 7
            if a(param(1)) < a(param(2))
                a(param(3)) = 1;
            else
                a(param(3)) = 0;
            end
            i = i+4; %simplify this using nmarap
        case 8
            if a(param(1)) == a(param(2))
                a(param(3)) =1;
            else
                a(param(3)) = 0;
            end
            i=i+4;
        otherwise
                error("unknown opcode");
    end
end

end