Decoder

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Course: ENCMP 100
% Assignment: 2
% Name:
% CCID:
% U of A ID:
%
% Acknowledgements:
% I refered to the MatLab documentation while writing.
%
% Description:
% This program is meant to decode a secret code according to rules outlined
% in the project description.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

clc;
clear;
code = int2str(input("Please enter a code to break: "));
days = ["Monday", "Tueday", "Wednesday", "Thursday", "Friday"];                                                                                 %%Day and location arrays for later use.
locations = ["the bridge.", "the library.", "the river crossing.", "the airport.", "the bus terminal.", "the hospital.", "St. Petes Church"];
intArr = (1:9);
if(length(code) == 9)  %%Test for correct code length
    sum = 0;
    for x = 1:length(code)  %%Put the code into an integer array
        intArr(x) = str2double(code(x));
    end
    for i = 1:length(intArr)  %%Sum all digits of the code
        sum = sum + intArr(i);
    end
    if(2*int8(sum / 2) == sum)  %% Test for even code
        day = intArr(1)*intArr(3) - intArr(5);
        if(day > 0 && day <= 7)  %%Test for valid day, 1-7
            if(rem(intArr(2)*intArr(4)-intArr(6), 3) == 0)  %%If divisible by 3
                loc = intArr(7) - intArr(9);
                if(loc > 0 && loc <= 7)  %%Test for valid location, 1-7
                    disp("Rescue on " + days(day) + " at " + locations(loc));   %%Print out message using the arrays from the start.
                else
                    disp("Decoy message: Invalid rendezvous point.");
                end
            else
                loc = intArr(8) - intArr(9);
                if(loc > 0 && loc <= 7)%%Test for valid location, 1-7
                    disp("Rescue on " + days(day) + " at " + locations(loc)); %%Print out message using the arrays from the start.
                else
                    disp("Decoy message: Invalid rendezvous point.");
                end
            end
        else
            disp("Decoy message: Invalid rescue day.");
        end
    else
        disp("Decoy message: Sum is odd.");
    end
else
    disp("Decoy message: Not a nine-digit number.");
end