How to limit number of repetition

I would need to run this code a specific number of time only (lets say n=30) and at the 30th times the user press on the keyboard, the program stops and creare a text file with the "fr" value reached at the 30th trial.

Here is my code so far:

global p

esc=0;

fr = 20;

while esc ~= 27

d.write(NISignal(fr))

esc = double(p);

if p == '1'

fr = fr+1;

else

fr = fr-2;

end

end

function s = NISignal(freq)

global nxsec dur p

s = 2.6 + 1/4.5*cos(linspace(pi,(2*pi*freq*dur)+pi,nxsec*dur)');

plot(s);

text(1000,6.7,string(freq))

if waitforbuttonpress

p = get(gcf, 'CurrentCharacter');

end

[Jan]

This is not twitter: no # before the tags. Thanks.

Answer 1

[Jan]

Add a counter:

esc = 0;
num = 0;
while esc ~= 27 && num < 30
   ...
   num = num + 1;
end

if num == 30
   ...save your file
end

By the way, communicating through global variables is a really bad design. Prefer to provide the p value as another output argument.