Explain how many times a for loop will execute

I can add ires to see the result, I am not sure how to see how many times the loops will execute. If someone could explain how to do this that would be helpful. I have done several searches and tried using the break function, but if its really big number says -32687:32688, how does one tell how many times it loops. without counting each 64560 times. I have figured it out on smaller loops by putting the ii at the bottom of the code. This has a loop within a loop and I am lost.

ires = 0;
    for index1 = 10: -2: 1
        for index2 = 2:2:index1
           if index2 == 6
           break;
           end
      ires = ires + index2;
        end
    end

Answer 1

[Mario Malic]

ires = 0;
for index1 = 10: -2: 1
    for index2 = 2:2:index1
       if index2 == 6
       break;
       end
       ires = ires + 1; % index2 for what?
    end
end

MATLAB enters first loop with index1 = 10, then proceeds in the second loop with index2 = 2. Within second loop it checks the if condition and adds 1 to ires. When the 'if' condition is fulfilled, it exits the second loop, and returns in the first one with index1 = 8 and so on.

[Jorge Rodriguez]

i understand how it works, I just don't know how to see how many times it loops

[Mario Malic]

ires contains the number of loops done.

disp(ires)

[Jorge Rodriguez]

doesn't that just display what ires is and not the actual number of times it loops? I just don't understand how your supposed to understand how many times the loop is performed?

[Jorge Rodriguez]

ok if i add n_times=0; and then frprintf( 'number of times the loop %d\n',n_times);

I can see how many loops, but that is only for one loop not both loops. I hope this explains what i am asking.

ires = 0;n_times=0;
    for index1 = 10: -2: 1
        for index2 = 2:2:index1
           if index2 == 6
           break;
           end
      ires = ires + index2;
      n_times=n_times + 1;
        end
    end
    fprintf('ires is %d\n',ires);
    fprintf('number of times the loop %d\n',n_times);

[Mario Malic]

I misinterpred iris, thought that was the loop counter.

[Jorge Rodriguez]

so any other ideas?

[Mario Malic]

Your code is working, n_times counts both loops.

[Jorge Rodriguez]

Okay, I just thought it was counting loop one. Well i gave it a solid try. Thanks for your help.