Question

SHOW INPUT AND OUTPUT OF EVERYTHING .ALSO SCREEN SHOT THE RESULTS. PROGRAMMING IN PERL

2.8 Special Literals

Three special literals __FILE__, __LINE__, and __PACKAGE__ represent the current filename, line number, and package name at that point in your program.

They may be used only as separate tokens and will not be interpolated into strings.

#!/usr/bin/perl print

"File name ". __FILE__ . "\n";

print "Line Number " . __LINE__ ."\n";

print "Package " . __PACKAGE__ ."\n";

# theycan not be interpolated

print "__FILE__ __LINE__ __PACKAGE__\n";

Output_________________________

2.9 Accessing Array Elements When accessing individual elements from an array, you must prefix the variable with a dollar sign ($) and then append the element index within the square brackets after the name of the variable.

Array indices start from zero, so to access the first element you need to give 0 as indices. You can also give a negative index, in which case you select the element from the end, rather than the beginning, of the array.

#!/usr/bin/perl

@days = qw/Mon Tue Wed Thu Fri Sat Sun/;

print "$days[0]\n";

print "$days[1]\n";

print "$days[2]\n";

print "$days[6]\n";

print "$days[-1]\n";

print "$days[-7]\n";

Output_________________________

2.10 Sequential Number Arrays

Perl offers a shortcut for sequential numbers and letters. Rather than typing out each element when counting to 100

#!/usr/bin/perl

@var_10 = (1..10);

@var_20 = (10..20);

@var_abc = (a..z);

print "@var_10\n"; # Prints number from 1 to 10

print "@var_20\n"; # Prints number from 10 to 20

print "@var_abc\n"; # Prints number from a to z

Output_________________________

2.11 Array Size The size of an array can be determined using the scalar context on the array - the returned value will be the number of elements in the array –

#!/usr/bin/perl

@array = (1,2,3);

$array[50] = 4;

$size = @array;

$max_index = $#array;

print "Size: $size\n";

print "Max Index: $max_index\n";

Output_________________________

Answer 1

PROGRAM 1:

#!/usr/bin/perl

print "File name ". __FILE__ . "\n";

print "Line Number " . __LINE__ ."\n";

print "Package " . __PACKAGE__ ."\n";

# theycan not be interpolated

print "__FILE__ __LINE__ __PACKAGE__\n";

OUTPUT:

File name 1.pl
Line Number 5
Package main
__FILE__ __LINE__ __PACKAGE__

PROGRAM 2:

#!/usr/bin/perl

@days = qw/Mon Tue Wed Thu Fri Sat Sun/;

print "$days[0]\n";

print "$days[1]\n";

print "$days[2]\n";

print "$days[6]\n";

print "$days[-1]\n";

print "$days[-7]\n";

OUTPUT:

Mon
Tue
Wed
Sun
Sun
Mon

PROGRAM 3:

#!/usr/bin/perl

@var_10 = (1..10);

@var_20 = (10..20);

@var_abc = (a..z);

print "@var_10\n"; # Prints number from 1 to 10

print "@var_20\n"; # Prints number from 10 to 20

print "@var_abc\n"; # Prints number from a to z

OUTPUT:

1 2 3 4 5 6 7 8 9 10
10 11 12 13 14 15 16 17 18 19 20
a b c d e f g h i j k l m n o p q r s t u v w x y z

PROGRAM 4:

#!/usr/bin/perl

@array = (1,2,3);

$array[50] = 4;

$size = @array;

$max_index = $#array;

print "Size: $size\n";

print "Max Index: $max_index\n";

OUTPUT:

Size: 51
Max Index: 50

SCREEN SHOT OF OUTPUT: