How can i write multiple video files? with videoWriter?

I want to write multiple video files and my conditions are here

   j=1
   if (t >= 125)

    writerObj1 = VideoWriter('voilation1.avi');
    open(writerObj1);
    writerObj2 = VideoWriter('violation2.avi');
    open(writerObj2);

   disp("<--------- Violation Detected----------> ")

    vidname=strcat('writerObj',num2str(j));
    writeVideo(vidname,img1);  

    end 
    if(t ==600)

     close(vidname); 
    j=j+1;
    end

Answer 1

[KSSV]

X = rand(100,1) ;

writerObj1 = VideoWriter('Video1.avi');
writerObj2 = VideoWriter('Video2.avi');
writerObj1.FrameRate = 10;
writerObj2.FrameRate = 10;
% open the video writer
open(writerObj1);
open(writerObj2);
h1 = figure(1) ;
hax1=axes ;
hold on
h2 = figure(2) ;
hax2=axes ;
hold on
for i = 1:length(X)
    if X(i)<0.5
        plot(hax1,i,X(i),'.r')
        f1 = getframe(h1);
        writeVideo(writerObj1, f1);
    else
        plot(hax2,i,X(i),'.b')
        f2 = getframe(h2);
        writeVideo(writerObj2, f2);
    end
    % close the writer object
end
close(writerObj1);
close(writerObj2);

[Bilal qureshi]

But i need code in which one writer object created and it will write this file after completion of this video file it will create another writer object and it will write it and so on.

[KSSV]

Okay...you can do that..by placing the open and close writer object, at the required places.

[Bilal qureshi]

its not only two objects i want to make dynamically writing object with loop ??

how can i write like this

vidname=strcat('writerObj',num2str(j));
  writeVideo(vidname,img1);

[Walter Roberson]

You cannot. You need to call VideoWriter to create a new object for the new file. writeVideo does not accept a file name as a parameter, and there is no way to change the file name associated with a VideoWriter object after you have created the object.