sampling DSP equations using multi-dim. cell array in MATLAB

%6.FUNCTION SAMPLING PROGRAM: SINGLE & MULTIPLE (SUMMED) FUNCTION'S
%SAMPLING
disp('ADDITION/SAMPLING OF WAVES PROGRAM')
N=input('enter the number upto which sampling will occur:\n');
ss=input('enter desired sample spacing\n');
n=0:ss:N-1; % sampling step
tn=N/ss; % this is the total number of samples
p=input('number of individual equations:\n');
   eq_str{p,3}='setup' % matlab showed an error that eq_str() 's size is contanly increasing, preallocate for speed. hence this line.
for row=1:p
   fprintf('for equation number: %d \n',row)
   eq_data(row,:)=input('enter the equation:\n'); % data stored as a <p x tn> double
   eq_str{row,1}=input('re-enter equation[this is for title]:\n','s');  % stored as a <3x3> cell
end
% eq_data is an array that stores p no. of equations, each with n samples,
% the samples will be stored in the columns of this 2-D array
% eq_str stores the text input for display in the title of the plot


for row=1:p-1
 % this adds '+' to 2nd column of all rows
 eq_str{row,2}='+';
end
for row=1:p
   eq_str{row,3}=strcat(eq_str{row,1},eq_str{row,2});
   % concatenates 1st and 2nd columns and stores it in the 3rd column
   % concatenation with strcat() eliminates any trailing spaces, to keep trailing spaces, use horzcat()
   % see strcat() in help menu for further details
end

eq_str
T=strcat(eq_str{:,3})
% concatenates the 3rd column and strores it as a string in T.
% nb: eq_str(:,3) will result in error, it is used only for displaying purposes,
% to edit data, {} has to be used instead of () as i'v used here

if(p>1)
    y=sum(eq_data);
elseif(p==1)
    % for a single equation, sum(eq_data) will add all the samples and generate a number, stem() cannot plot a number, hence this line
    y=eq_data;
end

stem(n,y);
grid;
xlabel('Number of Samples');
ylabel('Amplitude');
title(['Addition/Sampling of waves: ',T]);
clearvars eq_data eq_str;

% memory cleared as when a different number of samples is
% desired, an array out of bounds type of error will generate, as
% eq_data() is a array whose columns have been fixed to the number of
% samples on the 1st run of this code.