Why doesn't print output anything on each iteration of a loop when I use sleep?

Question

Today in my college a teacher asked me a question. He wrote this code on the paper and said \"What will be the output of this code?\"

use warnings;

for (1          


        

Answer 1

Perl, and many other programs, line-buffer output by default. You can set $| to 1 if you need unbuffered output.