For-loop in MATLAB

I have a vector ( Corr_vector) i made a loop that runs the variable i 44 in 44 points and verifies if the value R=50 belongs to [x,y]. I ran this code and realized that it doesn't execute the break command and prints all the xand y values until the end. I only want to perform this loop until the conditions R>=x & R<=y are verified.

for i = 1:length(Corr_vector)
    x=i;
    y=i+44;
    if R>=x & R<=y
        disp(x);
        disp(y);
        break
    else
      i=i+44; 
      continue
    end
end

Answer 1

[James Tursa]

You should not modify the index variable i inside the loop:

for i = 1:length(Corr_vector)
      :
      i=i+44;  % this is bad program design, you should not modify i inside the loop

You should change your logic to avoid this practice.

Answer 2

[Walter Roberson]

Your code is equivalent to

Hidden_internal_upper_bound = length(Corr_vector);
if Hidden_internal_upper_bound < 1
    i = [];
else
    Hidden_internal_i = 0;
    while true
        if Hidden_internal_i >= Hidden_internal_upper_bound
            break;
        end
        Hidden_internal_i = Hidden_internal_i + 1;
        
        i = Hidden_internal_i;
        x = i;
        y = i+44;
        if R>=x & R<=y
            disp(x);
            disp(y);
            break
        else
          i = i+44; 
          continue
        end
    end
end

Notice that each time through, the i that you changed using i = i+44 gets replaced with the hidden internal loop variable.

You cannot escape from an outer for loop by changing the loop control variable to be out of range! Changes to loop control variables are erased as soon as the next iteration of the loop starts. The only time that a change to a loop control variable is not discarded is the case where there would be no more iterations of the loop.