Section for Week 2, Thursday, 1/21/99

EXAMPLES OF PERL PROGRAMMING
----------------------------

1)  Go over solutions to la1:
    1.1:
	$total=0;
	$num=0;
	while (<>) {
	    chomp;
	    $total+=$_;
	    $num++;
	}
	if ($num == 0) {
	    print "No numbers read.  What's up with that?\n";
	} else {
	    print "Read $num numbers, and they averaged ", $total/$num, "\n";
	}
    1.2:
	$length=0;
	while(<>) {
	    chomp;
	    if (length($_) > $length) {
	    	$length=length($_);
		$longword=$_;
	    }
	}
	if (!defined($longword)) {
	    print "No words read.  What's up with that?\n";
	} else {
         print "Longest length was $length, and such a word was: $longword\n";
	}


2)  Q's?

3)  Go over content-type line for alpha.cgi business (and www.PIC.ucla.edu).

4)  Read a number ($n) and a list of strings and then prints out the n'th
    string in the list:
    
    $n=<>;
    @v=<>;
    print $v[$n-1];

5)  Same as 4), but with a random string:
    srand;
    @v=<>;
    print $v[int(rand($#v+1))];
    
    NOTE: srand!!!

6)  Convert a raw telephone number such as 3105551212 to (310)555-1212:
    $_=<>;
    s/(\d{3,3})(\d{3,3})(\d{4,4})/($1)$2-$3/;
    print;

    Explain alternative of using a seperate string and the =~ op.
    THIS IS IMPORTANT FOR LA2!!!

7)  Read a list of strings and print in reverse order:
    print reverse <>;
    
    will do the job, but without using 'reverse':
    @v=<>;
    for($i=$#v; $i>=0; $i--) {
	print $v[$i];
    }