Sequential file save/output

I am reading multiple txt files in sequence (one at a time) and modifying the data by interpolating over nan values and then I want to write to the same file name, but adding an extension (such as .xyz) at the end of each original file name so that I know which files were modified. I am not sure whether to use dlmwrite, save, or sprintf?

Here is what I have so far:

fprintf('reading in tXYsb data from text files...\n\n') c = dir('*.txt'); d=length(c);

for q = 1:d

%ICPdata = []; for n = 1:numel(c) fid = fopen(c(n).name); ICPdata = textscan(fid,'%f %f %f %f %f');

    [pathstr,name,ext]=fileparts(c(n).name); 
   % ICPdata     = [ICPdata; ICPdata_new];

ICPdata = cell2mat(ICPdata); % gets rid of cells in following code

ICP_t = ICPdata(:,1); %2000 time (sec) ICP_x = ICPdata(:,2); % x position (ps71) ICP_y = ICPdata(:,3); % y position (ps71) ICP_s = ICPdata(:,4); %surface elev ICP_b = ICPdata(:,5); %bed elev

    fclose(fid);

ICP_data_array = [ICP_t, ICP_x, ICP_y, ICP_s, ICP_b];

ICP_xi=fixgaps(ICP_x); ICP_yi=fixgaps(ICP_y); ICP_si=fixgaps(ICP_s); ICP_bi=fixgaps(ICP_b);

Interp_ICP_radar_data = [ICP_t, ICP_xi, ICP_yi, ICP_si, ICP_bi];

% export data

fprintf('writing tXYsb data to text file...\n\n') save([name.xyz Interp_ICP_radar_data '.txt'],'-ascii','-tabs'); % dlmwrite(name '.text',Interp_ICP_radar_data,'delimiter','\t','precision','%10.3f') % filename = sprintf(name.xyz, x); % dlmwrite(Interp_ICP_radar_data, filename);

fprintf('finished.\n')

end

end