I want to make a hierarchical system with some tests. However, I don't understand why my code does not work..

"teste1" is a cell array (1 column) with a number from 0 to 5 in each row. The code for this is this one:

 teste1    = cell(size(catconsumo));
 teste1(:) = {'0'};
 mask       = strcmp(catconsumo, 'low') & strcmp(catpreco, 'low');
 teste1(mask) = {'1'};
 mask       = strcmp(catconsumo, 'medium low') & strcmp(catpreco, 'medium low');
 teste1(mask) = {'2'};
 mask       = strcmp(catconsumo, 'medium') & strcmp(catpreco, 'medium');
 teste1(mask) = {'3'};
 mask       = strcmp(catconsumo, 'medium high') & strcmp(catpreco, 'medium high');
 teste1(mask) = {'4'};
 mask       = strcmp(catconsumo, 'high') & strcmp(catpreco, 'high');
 teste1(mask) = {'5'};

However, not even my thesis supervisor can explain to me why this works. Since the strcmp will return a value of 0 or 1, there should be always "teste1(0)" or "teste1(1)", so we think it should always write on row 1. Can somebody explain me firstly why this works?!

Regardless of understanding why it works, I tried to use for my hierarchical system:

 teste2 = teste1;

 for k=2:(length(Preos2013S1)-1)
     if teste2{k} == '0'
        mask       = strcmp(catracio1, 'low') & strcmp(catpreco, 'high');
        teste2(mask) = {'A'};
        mask       = strcmp(catracio1, 'medium low') & strcmp(catpreco, 'medium high');
        teste2(mask) = {'B'};
        mask       = strcmp(catracio1, 'medium') & strcmp(catpreco, 'medium');
        teste2(mask) = {'C'};
        mask       = strcmp(catracio1, 'medium high') & strcmp(catpreco, 'medium low');
        teste2(mask) = {'D'};
        mask       = strcmp(catracio1, 'high') & strcmp(catpreco, 'low');
        teste2(mask) = {'E'};
     else
        teste2{k}={'V'};
     end
 end

Now what happens is that it ignores the "if" condition: even if there is not a 0 in the row, the result can be from 'A' to 'E'.

So, I tried with (I think) is the most logical way:

 teste2 = teste1;

 for k=2:(length(Preos2013S1)-1)
     if teste2{k} == '0'
        if strcmp(catracio1, 'low') & strcmp(catpreco, 'high')
        teste2{k} = {'A'};
        elseif strcmp(catracio1, 'medium low') & strcmp(catpreco, 'medium high')
        teste2{k} = {'B'};
        elseif strcmp(catracio1, 'medium') & strcmp(catpreco, 'medium')
        teste2{k} = {'C'};
        elseif strcmp(catracio1, 'medium high') & strcmp(catpreco, 'medium low')
        teste2{k} = {'D'};
        elseif strcmp(catracio1, 'high') & strcmp(catpreco, 'low')
        teste2{k} = {'E'};
        end
      else
        teste2{k}={'V'};
     end
 end

Now, results are only or '0' or 'V'. So I even tried like this:

 teste2 = teste1;

 for k=2:(length(Preos2013S1)-1)
     if teste2{k} == '0' & strcmp(catracio1, 'low') & strcmp(catpreco, 'high')
        teste2{k} = {'A'};
     elseif teste2{k} == '0' & strcmp(catracio1, 'medium low') & strcmp(catpreco, 'medium high')
        teste2{k} = {'B'};
     elseif teste2{k} == '0' & strcmp(catracio1, 'medium') & strcmp(catpreco, 'medium')
        teste2{k} = {'C'};
     elseif teste2{k} == '0' & strcmp(catracio1, 'medium high') & strcmp(catpreco, 'medium low')
        teste2{k} = {'D'};
     elseif teste2{k} == '0' & strcmp(catracio1, 'high') & strcmp(catpreco, 'low')
        teste2{k} = {'E'};
     else
        teste2{k}={'V'};
     end
 end

Even worst: now everything is 'V'. Can somebody please help me understanding what the hell is wrong?! I just want to use the strcmp in the rows where teste2 is '0'. If its not 0, I want a 'V', regardless of 'strcmp' results.