Sangeeta Arora

• Nov 20th, 2007

 

Stack is LIFO (Last in First out), In perl that could be inplemented using the push() and shift() functions. push() adds the element at the last of array and shift() removes from the beginning of an array.

Gayathri Sureshbabu

 Profile Answers by Gayathri Sureshbabu 

• Apr 10th, 2008

 

push() shift() implements FIFO

To achieve LIFO, shift and unshift() can be used.
unshift inserts value into array in first position.
shift returns the value from the first position of the array.

maruthr

 Profile Answers by maruthr 

• Apr 16th, 2008

 

Stacks and queus in Perl

IN
unshift =>     -------------------------------------------     <= push 
                     |         |          |          |          |        |
shift    <=      --------------------------------------------    =>pop
OUT
                     Figure 1.1: Demonstrate stacks and queues in Perl

Stack: Stack is a important data structure In Perl programming, and can be implemented using LIFO technique. i.e., the Last thing In is the First thing Out.
So from the above demonstration(refer Figure 1.1), it's learnt that Stacks can be implemented using PUSH and POP commands.

Queue: The queue is another data structure. A physical analogy for a queue is a line at a bank. When you go to the bank, customers go to the rear (end) of the line and customers come off of the line (i.e., are serviced) from the front of the line.
So from the above demonstation(refer Figure 1.1), we can say that Queues can be implemented using PUSH and SHIFT.

wow_suraj

 Profile Answers by wow_suraj 

• May 2nd, 2008

 

In perl stacks are easy to be implemented. Stacks which follows LIFO (Last In First Out) data structure can be handled in perl with 'POP' and 'PUSH' keywords. 

POP Example:
my $strTest = POP(@arrTest);
print "$strTest";

In this example, the Last element present in @arrTest will be poped and will be assigned to variable $strTest (LIFO). Suppose the array contains value "STAR" at it's last position thus the next line of the code will populate STAR.

PUSH Example:

PUSH(@arrTest, $strTest) if ($strTest);

In this example, we are pushing $strTest variable to the array @arrTest. After the PUSH statement the array size will be increased by one and the last element of the array will be the value contained in variable $strTest. 
 

singh_Pushpendra

 Profile Answers by singh_Pushpendra 

• Aug 13th, 2010

 

#! /usr/bin/perl -w

$str1="Pushpendra Singh";
@str=split("",
$str1);

@stack_array=();
foreach $i (@str){
print "nt
Item being pushed is : $i";
push(@stack_array, $i);

sleep 1;
}

print "nt Popping out the stack";

$len=@stack_array;
for($i=$len; $i>=0; $i--,$len--){
if($len==0){

exit 0;
}
print "nt Popped item is : ".pop(@stack_array);

sleep 1;
}
print "nt";

shah

• May 16th, 2018

 

Its wrong sangeeta. To implement a stack in perl, we have to use push and pop function, push will add an element at the end of array and pop will remove the element from the end of array