How to concatenate of results from a loop

   The output identifies the elements of X that are smaller than the product of their two indexes.
for example;
X=[1 1;0 4;6 5];
p=[];
[col,row]=size(X);
for c=1:col
for r=1:row
if (r*c)<X(r,c)
p=cat(1,p,[r c]);
else
p=[];
end
end
end

The answer should be 2 1 1 2 3 2 But I'm getting only last one i.e. 3 2. What could be wrong in my code? Please help me

[John D'Errico]

This is not a tag: "if i remove ; form statement under if i will get p=2 1 p=1 2 p=3 2"

[Roger Stafford]

@Sunil. The problem in your code is that you should not have the two ‘else’ code lines:

else
p=[];

You should simply do nothing whenever the condition is untrue. As it stands, whenever you have an element of X that does not satisfy your condition, then all the work you have done on p to accumulate results is wiped out by the deletion “p=[]”. That is presumably why you saw only the last output.

[Sunil Kunjachan]

But if you try with X=[0;1;2;3;4;5;6;7;8;9;10],the code will work.

[Sunil Kunjachan]

I'm trying to get the for X=[1 1;0 4;6 5]. I know the answer. It will be [2 1;1 2;3 2]. I'm getting only last row in that matrix.

Answer 1

[Andrei Bobrov]

    X=[1 1;0 4;6 5];
    [r,c] = find((1:size(X,1))'*(1:size(X,2)) > X);
    p = [r,c];

[Sunil Kunjachan]

Thanks for the reply. But I'm not getting the answer!

[Andrei Bobrov]

fixed :)