How can I change the name of a variable?

I want to change the name of a variable, X which is the output from my simulink model, according to my input variable, np.

For example:

for i=1:2
    np = input(':'); % let's say, for i=1 , np=50
    sim('Simulink_Model'); % Output: X
    sprintf('X%d',np) = X; % Now I want the output X to be X50
end

Answer 1

[Azzi Abdelmalek]

Read this http://matlab.wikia.com/wiki/FAQ#How_can_I_create_variables_A1.2C_A2.2C....2CA10_in_a_loop.3F you will know that it's not a good idea to create such name variables, you can just use one cell array

for ii=1:2
  sim('Simulink_Model'); % Output: X
  out{ii} = X;  
end