Matrix dimensions must agree error, confused because it works sometimes and I don't even have a matrix as far as I know.

So I have to code a game in matlab and I'm making a text based adventure RPG kind of thing, so I'm making demo codes for figuring out how to make attack mechanics.

clc
clear

attack1 = input('Choose your attack: \nPunch\nKick\n\n>>', 's');

critchance = randi(100);

damage = 0;

if attack1 == 'Punch'
    damage = randi(20)+30;
     if critchance >= 80;
        damage = 2*damage;
    end
elseif attack1 == 'Kick'
    damage = randi(65)+15;
elseif attack1 == 'Call him ugly'
    damage = 1000;
else
    fprintf('That attack doesnt work!')
end

fprintf('Your attack did %.0f damage!',damage)

When I input Punch it works perfectly, but when I do Kick or anything else it says theres in error in the " if attack1 == 'Punch' " Line because the matrix dimensions don't agree. Thanks for any help!

Answer 1

[James Heselden]

Simple solution: for your if/ifelse conditions you are using char arrays, swap these out to strings by replacing:

% e.g. replace
'Punch'

% with 
"Punch"

So your code becomes:

clc
clear
attack1 = input('Choose your attack: \nPunch\nKick\n\n>>', 's');
critchance = randi(100);
damage = 0;
if attack1 == "Punch"
    damage = randi(20)+30;
     if critchance >= 80;
        damage = 2*damage;
    end
elseif attack1 == "Kick"
    damage = randi(65)+15;
elseif attack1 == "Call him ugly"
    damage = 1000;
else
    fprintf('That attack doesnt work!')
end
fprintf('Your attack did %.0f damage!',damage)

In your type of situation; it is often better to use the Switch Statement.

clc
clear
attack1 = input('Choose your attack: \nPunch\nKick\n\n>>', 's');
critchance = randi(100);
damage = 0;
switch attack1
    case 'Punch'
        damage = randi(20)+30;
         if critchance >= 80;
            damage = 2*damage;
        end
    case 'Kick'
        damage = randi(65)+15;
    case 'Call him ugly'
        damage = 1000;
    otherwise
        fprintf('That attack doesnt work!')
end
fprintf('Your attack did %.0f damage!',damage)

Good luck and on a side note, don't forget to add a \n to the end of a fprintf to make the output a bit cleaner.

Regards

James

[Rik]

Another solution is to use strcmp to compare two char arrays. The reason for the error is that a char array (single quotes) is an array of characters, while a string scalar (double quotes) can contain multiple characters.