Legend of Many curves on one graph?!

Hello, I would like to have a legend that is on a for-loop so for each entry I would like to have a name of my data , how can I do it ? I have tried the following line but it doesn't work!

for i=1:5
    load all my file .*mat
    do some calculations 
    plot(data)
    legend (num2str(i))
    hold on
  end

Answer 1

[KSSV]

N = 5 ;
str = cell(N,1) ;
for i=1:N
    % load all my file .*mat
    % do some calculations
    plot(rand(10,1))
    str{i} = num2str(i) ;
    hold on
end
legend(str)