How do I write a new wave file based on frame selected?

Dear all, I am new to signal processing, and I am trying to write a new wave file using a segment I am selecting from a plot. Below is what I have so far, but I am stuck and don't know how to actually write a wave file. Please help!

%If you have not established a .wav file - do so! clear,clear all % comment this out if you are using the same file [filename, pathname]=uigetfile('*.wav', 'Select a wave file');% comment this out if you are using the same file [y, fs] = audioread(fullfile(pathname, filename));% comment this out if you are using the same file

%Next step is simple- do you want to hear your .wav file?

q3= input('Would you like to segment your .WAV file?(y/n)');

 %at this point variable q1 will contain whatever answer the user puts in
if strcmpi(q3,'y')% this looks at the answer

    t=0:1/fs:(length(wave)-1)/fs; % get sampling frq
 plot(t,y);
  figure(1);
           plot(t,wave);
           title('Wave File');
           ylabel('Amplitude');
           xlabel('Length (in seconds)');%plots a raw spectrogram of your data. This doesn't include much info, it's just for you to select point of time
disp('Now select your beginning');
[x1,y1]=ginput(1);% this is the point of time for your new segment
disp('Now select the end of your new segment');
[x2,y2]=ginput(1);
else

end