Rock, Paper, Scissors in MATLAB - matlab

Question

Alrighty, it's that time of week again where I am officially throwing my hands up in the air with MATLAB and asking for help. My goal this week is to try and make a function that takes in two inputs, which are strings that say 'Rock, Paper, Scissors' (or whatever the choices are), it then outputs one of three strings 'Player 1 Wins!', 'Player 2 Wins!' or 'Keep Playing!'. To win, the player must beat the other two out of three times (a tie counts as a loss for both players)
function[winner] = RockPaperScissors(player1, player2)
[move1, others] = strtok(player1, ',');
[move2, rest] = strtok(others, ',');
[move3, ~] = strtok(rest, ',');
[go1, others] = strtok(player2, ',');
[go2, rest] = strtok(others, ',');
[go3, ~] = strtok(rest, ',');
Counter1 = 0;
Counter2 = 0;
for i = 1:3
if strcmp(move1, 'Rock') && strcmp(go1, 'Paper')
Counter2 = Counter2 + 1;
elseif strcmp(move1, 'Rock') && strcmp(go1, 'Scissors')
Counter2 = Counter2 + 1;
elseif strcmp(move1, 'Rock') && strcmp(go1, 'Rock')
Counter1 = 0;
elseif strcmp(move1, 'Paper') && strcmp(go1, 'Paper')
Counter1 = 0;
elseif strcmp(move1, 'Paper') && strcmp(go1, 'Rock')
Counter1 = Counter1 + 1;
elseif strcmp(move1, 'Paper') && strcmp(go1, 'Scissors')
Counter2 = Counter2 + 1;
elseif strcmp(move1, 'Scissors') && strcmp(go1, 'Scissors')
Counter1 = 0;
elseif strcmp(move1, 'Scissors') && strcmp(go1, 'Paper')
Counter1 = Counter1 + 1;
elseif strcmp(move1, 'Scissors') && strcmp(go1, 'Rock')
Counter2 = Counter2 + 1;
end
if strcmp(move2, 'Rock') && strcmp(go2, 'Paper')
Counter2 = Counter2 + 1;
elseif strcmp(move2, 'Rock') && strcmp(go2, 'Scissors')
Counter2 = Counter2 + 1;
elseif strcmp(move2, 'Rock') && strcmp(go2, 'Rock')
Counter1 = 0;
elseif strcmp(move2, 'Paper') && strcmp(go2, 'Paper')
Counter1 = 0;
elseif strcmp(move2, 'Paper') && strcmp(go2, 'Rock')
Counter1 = Counter1 + 1;
elseif strcmp(move2, 'Paper') && strcmp(go2, 'Scissors')
Counter2 = Counter2 + 1;
elseif strcmp(move2, 'Scissors') && strcmp(go2, 'Scissors')
Counter1 = 0;
elseif strcmp(move2, 'Scissors') && strcmp(go2, 'Paper')
Counter1 = Counter1 + 1;
elseif strcmp(move2, 'Scissors') && strcmp(go2, 'Rock')
Counter2 = Counter2 + 1;
end
if strcmp(move3, 'Rock') && strcmp(go3, 'Paper')
Counter2 = Counter2 + 1;
elseif strcmp(move3, 'Rock') && strcmp(go3, 'Scissors')
Counter2 = Counter2 + 1;
elseif strcmp(move3, 'Rock') && strcmp(go3, 'Rock')
Counter1 = 0;
elseif strcmp(move3, 'Paper') && strcmp(go3, 'Paper')
Counter1 = 0;
elseif strcmp(move3, 'Paper') && strcmp(go3, 'Rock')
Counter1 = Counter1 + 1;
elseif strcmp(move3, 'Paper') && strcmp(go3, 'Scissors')
Counter2 = Counter2 + 1;
elseif strcmp(move3, 'Scissors') && strcmp(go3, 'Scissors')
Counter1 = 0;
elseif strcmp(move3, 'Scissors') && strcmp(go3, 'Paper')
Counter1 = Counter1 + 1;
elseif strcmp(move3, 'Scissors') && strcmp(go3, 'Rock')
Counter2 = Counter2 + 1;
end
if max(Counter1, Counter2) == Counter2
winner = 'Player 2 Wins!';
elseif max(Counter1, Counter2) == Counter1
winner = 'Player 1 Wins!';
elseif max(Counter1, Counter2) ~= (Counter1 || Counter2) % I tried making a Counter 3, did not work out
winner = 'Keep Playing!';
end
end
As you can see, I have most of this bad boy running. My issue now is that when I run the test case ' [winner1] = rockPaperScissors('Rock,Scissors,Scissors','Paper,Rock,Scissors')
It outputs my answer in a vertical 'ans' and not as winner. Additionally, it gives me 'Player 2 Win!' even though it should be a tie. I tried debugging it all, but can't figure out where my issue is. Bah!

Answer 1

Have you actually thought about using a table? It's perfect for your purpose!
Just an idea, how to do it alternatively. Please don't nail me on the fact, that I haven't considered all your restrictions and conditions, but it should be easy for you to adapt my function how you like it.
function RockPaperScissorsLizardSpock(player1, player2, rounds)
%// creating the table with all combinations
header = {'Rock';'Paper';'Scissors';'Lizard';'Spock'};
Rock = [0;-1;1;1;-1];
Paper = [1;0;-1;-1;1];
Scissors = [-1;1;0;1;-1];
Lizard = [-1;1;-1;0;1];
Spock = [1;-1;1;-1;0];
T = table(Rock,Paper,Scissors,Lizard,Spock,'RowNames',header);
%// play and display winners of every round
points = 0;
for ii = 1:rounds
pointsRound = T{player1(ii), player2(ii)}; %// no need for if-conditions
%// one line is enough
points = points + pointsRound;
if pointsRound > 0; disp(['Player 1 wins round ' num2str(ii) '!'])
elseif pointsRound < 0; disp(['Player 2 wins round ' num2str(ii) '!'])
else disp(['Draw in round ' num2str(ii) '!'])
end
end
%// display overall winner
if points > rounds/2; disp('Player 1 Wins!')
elseif points == 0; disp(['Draw!' num2str(ii) '!'])
else disp('Player 2 Wins!')
end
and now lets play:
player1 = {'Rock','Scissors','Scissors'}
player2 = {'Paper','Rock','Scissors'}
RockPaperScissorsLizardSpock(player1, player2, 3)
returns:
Player 1 wins round 1!
Player 1 wins round 2!
Tie in round 3!
Player 1 Wins!
you can also implement some advanced features, for example give names to the players:
function RockPaperScissorsLizardSpock(player1, player2, rounds)
plname = inputname(1);
p2name = inputname(2);
...
if pointsRound > 0; disp([plname ' wins round ' num2str(ii) '!'])
...
else disp([p2name ' Wins!'])
end
and
Sheldon = {'Spock','Spock','Spock'}
Penny = {'Paper','Rock','Scissors'}
RockPaperScissorsLizardSpock(sheldon, penny, 3)
yields
Sheldon wins round 1!
Penny wins round 2!
Penny wins round 3!
Penny Wins!
If you insist on your string input with commas:
Sheldon = 'Spock,Spock,Spock'
Penny = 'Paper,Rock,Scissors'
you need to add strsplit to the function:
player1= strsplit(player1,',')
player2= strsplit(player2,',')

Answer 2

You need to use the function strcmp instead of the == operator. The inputs are char arrays, which is why == is complaining about the dimensions.
Here's an example for your first if statement:
if strcmp(move1, 'Rock') && strcmp(go1, 'Paper')
winner1 = 'Player 2 Wins!';
Here I've made 2 changes, the first is to use strcmp, and the second to use scalar AND i.e. &&
See help strcmp and help && for more details.