How to save variables and put them in a vector

I have this code in which i input a value, let's call it x. The code runs, and afterwards it stores a value called y. For each different x there's another y. What i want to do is each time i input an x it stores its value on a vector and the value from y on another vector so i can later plot them together.

Answer 1

[Walter Roberson]

Example:

num_runs = 10;
all_x = zeros(num_runs, 1);
all_y = zeros(num_runs, 1);
for K = 1 : num_runs
  x = randi([-K K], 1, 1);
  y = x.^2;
  all_x(K) = x;
  all_y(K) = y;
end

[Feliciano Döring]

Hey, thanks for the reply, one thing though, I manually input x and run the program, then it gives me some variables and i calculate y with them, after that i change x and run the program again. The way I tested the code that you gave me wouldn't work with my case because i need to store the value for each time i run

[Walter Roberson]

   persistent all_x all_y
   x = input('Enter an x value ');
   r = rand() * sqrt(x);
   y = atan2(r, x);
   all_x(end+1) = x;
   all_y(end+1) = y;

[Feliciano Döring]

In this case all_y and all_x are storing the variables somewhere or do i need to put my variables as cell arrays o i can store them properly?

[Walter Roberson]

Script version:

   global all_x all_y
   x = input('Enter an x value ');
   r = rand() * sqrt(x);
   y = atan2(r, x);
   all_x(end+1) = x;
   all_y(end+1) = y;

Or better for the script case:

if ~exist('all_x', 'var'); all_x = []; all_y = []; end
 x = input('Enter an x value ');
 r = rand() * sqrt(x);
 y = atan2(r, x);
 all_x(end+1) = x;
 all_y(end+1) = y;

all_x and all_y are storing all runs of the values. You would only need cell arrays if your values are not scalar numeric values.