# Change a for loop iteration if condition is met

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Richard Wolvers on 18 Jun 2017
Answered: Julian Hapke on 20 Jun 2017
Hello everyone,
I have the following problem. I want to stop an iteration in a for loop if a certain condition is met and then let the iteration continue from another value (in other words, skip certain iterations). In the below example the end values should be: b=20 and c=0. (Because the iteration goes to 50, the elseif condition wil never be met). How can i do this?
a= 5;
b=0;
c=0;
for t=1:100
a = a+t
if a == 20
b = 20;
% then the iteration should stop and start from t=50
elseif a == 30
c = 20;
% Then the iteration should stop and start from t=70
end
end
dpb on 18 Jun 2017
That's inconsistent problem statement; a can never be anything between 20 and 70 because when t becomes 50 the sum immediately passes 30.
Need to write the specification more precisely first, then if it can actually be met as not logically inconsistent, use of a while loop with computed t value instead of counted for will probably be the solution.
Sagar Doshi on 20 Jun 2017
You can use break in your loop as mentioned in the documentation link here to come out of the loop and have another loop to start with required value for 'a' and 't'.

Julian Hapke on 20 Jun 2017
with a while loop:
a=5;
b=0;
c=0;
t = 1;
while t <=100
a = a+t;
if a == 20
b = 20;
t = 50;
elseif a == 30
c = 20;
t = 70;
else
t = t+1;
end
end
but have in mind, that this is nonsense, as dpb pointed out.