How to store a specific value in for loop when something happens in that loop

here is one dummy problem regarding my question.

for i=1:5
    A(:,:,i) = magic(3)*i;
end
for i = 1:5
   for n = 11:100
       x(i) = n*A(1,1,i);
       if (x>480)
         break
       end
    end
   n(i)=n;
end

Now here I want to save all 5 of n values for which x is greater than 480 and it will break loop of n.

[Stephen23]

See Guillaume's answer for an excellent explanation and better solution.

Answer 1

[KSSV]

for i=1:5

    A(:,:,i) = magic(3)*i;

end

count = 0 ;

iwant = [];

for i = 1:5

    for n = 11:100

        x(i) = n*A(1,1,i);

        if (x>480)

            count = count+1 ;

            iwant(count) = n ;

            break

        end

    end

    n(i)=n;

end

Note: Considering allocating the matrices at the begin

[Shaikh Hossain]

Thanks...it actually worked this way

Answer 2

[Guillaume]

Your dummy example does not work because you're using the same variable name, n, for indexing and storing the threshold index. If you used any other variable, such as thresholdindex it would work:

thresholdindex = zeros(1, 5);
for i = 1:5
   for n = 11:100
      if n*A(1,1,i) > 480
          break;
      end
   end
   thresholdindex(i) = n;
end

Now a few comments:

• You don't preallocate any of the arrays in your dummy example. Make sure you do in your real code as I've done above.
• Use meaningful variable names. thresholdindex tells the purpose of the variable, n does not.
• Are you sure you need loops? your dummy example could be achieved with this:

n = 11:100;
[~, thresholdindex] = max(bsxfun(@times, squeeze(A(1, 1, :)), 11:100) > 480, [], 2);
thresholdindex = thresholdindex' + n(1)-1

[Shaikh Hossain]

Thanks for your help :)