why "while loop" is not working?

Hi! My task is to find all nodes that go after node "3" in directed graph "gr". In order to make it I used the "successors" function and while loop. But while loop is not working. Can anybody help me please? Here's the code:

clc;
A = [1 2 3 4 5 6 7];
B = [2 3 4 5 6 7 8];
w = [0 0 1 0 0 0 0];
gr = digraph (A,B, w);
N = successors (gr,4)
i=0;
while TF == 0
    TF = isempty (N);
    N = successors (gr, N);
    i = i + 1;
    N(i)= N;
end

[madhan ravi]

What’s TF ?

[Artur Iskhakov]

It is a variable that equals to logical 1 when matrix "N" is empty and to logical 0 when matrix "N" is not empty.

Answer 1

[Vashist Hegde]

To check what was going on, I wrote a small while loop on my own -

This while loop is also not working. The similarity between this code and your code is that you have not initialized TF. so when I put break points, and ran this stepwise, I found that when a variable is not initialized and is used, it is by default set to 1.

So TF has a value of 1, and hence the loop is never entered.

I suggest you to initialize TF.

while TF==0
    disp('hi');
    TF=1;
    var = randi(5);
    if var==4
        TF=3;
    end
end

[Artur Iskhakov]

thank you! )))