How to compute bowling game score

Problem:

"The function should return the score of 'bowling game' from the given input argument vector. If the input is not a valid sequence it should return -1. example input [9 1 0 10 10 10 6 2 7 3 8 2 10 9 0 9 1 10] ; output score is 168."

I have tried to code for computing the game score for the above mentioned bowling problem and for some inputs it turns wrong score; for example for the input [1 9 2 8 3 7 4 6 5 5 6 4 7 3 8 1 9 1 10 1 1]

[Conditions: Strike counts 10+sum of pins knocked down by the next two balls. Spare counts 10 + the pins knocked down by the next ball. open counts the number of pins knocked down in that frame. Bonus ball counts the number of pins it knocked down.

function scores = bowl(games)
  dummy = games;
  [r, c] = size(dummy);
  games=dummy;
  % reshaping the given input vector by plugging zeros after strikes:
  for idx = 1 : 2 : 19
   if games(idx) == 10
    games = [games(1 : idx), 0, dummy(idx +1 :c)]
    dummy = games
    [r, c] = size(dummy);
   end
  end
  % invalid input verification
  if length(games)<20 
     scores=-1;
  elseif length(games)>20 && (games(19)+games(20))~=10
      scores=-1;
  else
      %score computation
   games = [games, zeros(r, 1)];
   lastwasstrike = games(:, 19) == 10;
   games(lastwasstrike, 21 : 22) = games(lastwasstrike, 20 : 21);
   games(lastwasstrike, 20) = 10;
   startscores = sum(games(:, 1:20), 2);
   isspare = games(:, 1:2:19) + games(:, 2:2:20) == 10;
   sparescores = sum((games(:, 3:2:21).*isspare), 2);
   isstrike = games(:, 1:2:19) == 10;
   strikescores = sum((games(:, 4:2:22).*isstrike), 2);
   isdoublestrike = games(:, 1:2:17) == 10 & games(:, 3:2:19) == 10;
   doublestrikescores = sum((games(:, 5:2:21).*isdoublestrike), 2);
   scores = startscores+sparescores+strikescores+doublestrikescores;
  end
end

[Walter Roberson]

Your code for plugging 0's is wrong. Consider what it does if the first two balls are both strikes.

Answer 1

[Geoff Hayes]

Surya - you may want to reconsider the lines

 lastwasstrike = games(:, 19) == 10;
 games(lastwasstrike, 21 : 22) = games(lastwasstrike, 20 : 21);
 games(lastwasstrike, 20) = 10;

What is the purpose of determining whether the last frame generated a strike? Why replace the "eleventh frame" with one of the values from the tenth frame? And why initialize the 20th element of the games array to 10? If I comment out these lines, then I seem to get the correct answer for both your examples (from above).

Answer 2

[Jenny Lay]

I had a similar question and this was what i did:

function final_score=bowl(num_p)
    clear all
    clc

      total = 0;   

      function initial_check()
          if length_of_inputs>21 || length_of_inputs<12          
              total=-1;   
          end

          for n0=1:length_of_inputs   
              if num_p(n0)>10 || num_p(n0)<0   
                  total=-1;   
              end
          end
      end

      function second_check()
          if k1>10   
              total=-1;   
          end
      end

      num_p=input('Enter the number of pins: ');   
      length_of_inputs=length(num_p);   
      n=length_of_inputs-3;   
      x=1;   
      n1=1;   

      %frame 1~9
      while n1<=n;   
          initial_check();   
          k1=num_p(n1)+num_p(n1+1);   
          if num_p(n1)==10   %strike
              sum_k1(x)=num_p(n1)+num_p(n1+1)+num_p(n1+2);
          elseif k1==10   %spare
              second_check();   
              sum_k1(x)=k1+num_p(n1+2);   
              n1=n1+1;   
          else   %open
              second_check();   
              sum_k1(x)=k1;   
              n1=n1+1;   
          end
          x=x+1;   
          n1=n1+1;   
      end
      fsum_k1=cumsum(sum_k1);  

      %frame 10 (last frame)
      n=n+1;   
      sum_k2=num_p(n)+num_p(n+1)+num_p(n+2);   
      k2ab=num_p(n)+num_p(n+1);   
      if k2ab<10   
          fsum_k2=k2ab;   
      elseif sum_k2>30   
          disp(-1)   
      else
          fsum_k2=sum_k2;   
      end

      last_score=fsum_k1(end)+fsum_k2;   
      final_score=[fsum_k1,last_score];   

      if total==-1  
          final_score=-1;   
      end
  end