Conditional and Loops:
Let me explain looping constructs other than Swith-case.
if-elsif-else
Following is the syntax for if-elsif-else .
if(condition)
{
......;
}
elsif(condition)
{
.........;
}
else
{
..........;
}

Following is the contradicted version of it

unless(condition)
{
........;
}
if the condition returns false, then the set the statements in between braces gets executed.
This is similar to if(!condition)

Braces after the if statement are required if there are bunch/block of statements to execute.
Following example explains in detail...

my $var=1;
if($var==1)
{
print "Bunch of Statements"."\n";
}
$var=0;
unless(!$var==1)
print("I am in unless condition");

Output:
Bunch of Statements
I am in unless condition

While statement
Following is the syntax for While conditional statement

while (condition)
{
........;
}

Following is the contradicted version of it

untill(condition)
{
...........;
}

Following is the example for while conditional statement

my $num=1;
while($num)
{
print "I am in While"."\n";
$num=0;
}
until ($num==1)
{
print "I am in untill"."\n";
$num=1;
}

Output:
I am in While
I am in untill

For Loop

for(variable_initialization;condition;iteration)
{
........;
}

Following is the example for 'for' loop

my $num=3;
my $vi;
for($vi=0;$vi<=$num;$vi++)
{
print $vi."\n";
}

Output
0
1
2
3

Foreach statement

Following is the syntax for 'foreach' statement

foreach(condition)
{
.............;
}

Example

my @ar=("One","Two","Three");
foreach(@ar)
{
print "List element $_"."\n";
}

Output:
One
Two
Three

After such a long time I am posting few of my learning's on Perl...

Variable Scoping:
In general variables are declared using "my".
my $var= "hello";
Actually its not required. Just use
$var="hello";
Both the statements print "hello".
But the second statement creates global variables throughout the program, which is not recommended.
Using 'my' creates lexically scoped variables. Say bunch of statements surrounded by curly-braces.
The variables declared in between braces are different.

my $var="Hello";
my $num=1;
if($num==1)
{
my $var1="World";
print $var."\n"; #prints Hello
print $var1."\n"; #prints World
}
print $var1; #prints nothing

Output:
Hello
World

Using "my" in combination with a 'use strict;' at the top of the Perl script means that the interpreter will pick up certain common programming errors.
Add 'use strict;' at the top of the script and execute the same script. The final print statement 'print $var1;' would display compile-time error and fail to execute the script.
So add 'use strict;' in the program, which is recommended.

Anonymous Variables @ PERL

My friend had told me how anonymous variables are handled in PERL. I really felt very interesting... let me share the same with you...

Anonymous Variables: If a variable is declared in anonymous mode, it treats like memory allocation. It's important first to understand how your OS and libraries handle memory and depends on 32-bit/64-bit machine.
These variables are not referred by names.
Let's look into the details how PERL handles these variables...

Scalar Variable Handling Array values...

A reference is a scalar value and can refer to any other Perl data type.
A scalar variable can be declared providing list of array values.
>my $Scal = [1, 2, 3, 4];

Here the scalar variable wont handle the list of values, it handles the address where the array is located.
Each and every variable in the list is accessed using its index.

For Example:
#Annonymous for ARRAY
my $var1 = [1,2,3];
print("Array details are ");
foreach (@{$var1})
{
print ;
}

Result:
Array details are 123

Note: @{var1} is an array, but when it is used in scalar context then it returns number of elements contained in it.

Scalar Variable Handling Hash Variables...

Storing a reference as the value of an hash element, can easily create lists and hashes within lists and hashes.

For Example:
#Annonymous for HASH
my $var1 = { aa => "Synergy", ab => "Change", ac => "Integrations" };

foreach ( keys(%$var1) ) #returns the Key values for Hash Variable
{
print "$$var1{$_} \n";
}

Result:
Change
Integrations
Synergy

Here '$_' refers to "default variable",It's used as the default argument to a number of functions in Per

For obtaining individual values we need to refer to each element

For Example:
#Annonymous for HASH
my $var1 = { aa => "Synergy", ab => "Change", ac => "Integrations" };
print "\nFirst Value =>" ,"$var1->{'aa'}" . "\n";

Result:
First Value =>Synergy

Here it goes another interesting example...

my $var1 = { aa => { a => 'Change', b => 'Integration'} };
print "$var1->{'aa'}->{'a'}\n";

Result:
Change

This is 2 level hash of hash structure using anonymous hash references. Sounds Cool!!!