How can i run the loop of the function with many other sub functions

I am very new in MATLAB and cannot understand that how can i set my function in a loop. Appreciate if anyone can help me.

khan.m # suppose function name

Inputs of the function are the following

Y1=zahid(a); # zahid.m is a sub function with input argument “a” in main function khan.m.
Y2=shahid(b);# shahid.m is a sub function with input argument “b” in main function khan.m.
Y3=data1(:,3);# third column of the function data.m as a input argument (suppose size of this vector is 122 by 1).

Output of the function is following

R # a vector of measurements of size 122 by 1.

Now i want to check the some condition over the vector R and if that condition is true then want to update the vector Y3 only ,having the other inputs same. For example

if    max(R)>3  # suppose the condition which i have to check.
 j = find(R==max(R), 1); # find the index of maximum value of vector R.
Y3-Y3(j), update the vector Y3 such that delete measurement “j” from vector Y3.
else 
stop # if above condition is not true stop the looping of the function khan.m

Note: I do not understand that how can i repeat khan.m if the above condition suppose remain true up to 5 times and i will continue update the vector Y3 i.e after five runs there will be 117 observation in Y3.