If your intent is to reverse the @number array, why not write it like this?

my @number = (1,2,3,4);
my @rev = reverse @number;
print "@rev\n";
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I want to do it without using any predefine function

In Perl arrays, the index '-1' accesses the last element in the array. '-2' accesses the second-to-last. ...and so on, down to '- scalar @array', which will be the same element as '$array[0]'.

This makes it easy to simultaneously count upward and downward; just do a numeric negation of sign, and adjust for off-by-one.

@numbers = ( 100, 200, 300, 400, 500 );

$reversed[$_-1] = $numbers[-$_] for 1 .. @numbers;

print "$_\n" for @reversed;
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Here's just about the only useful use of $[ (which should be avoided, even here).

@numbers = ( 100, 200, 300, 400, 500 );

{
  no warnings 'deprecated';
  local $[ = 1;             # Don't do this... example only.

  $reversed[$_] = $numbers[-$_] for 1 .. @numbers;
}

print "$_\n" for @reversed;
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Dave

I want to do it without using any predefine function

I.e., "This is homework".

try the push function to add an element to an array.

This session under the debugger shows two possible ways of doing what you want.

  DB<1>  @c = (1,2,3,4);

  DB<2>  for ($i = $#c; $i>=0;$i--) {push @d,  $c[$i]};

  DB<3> x @d
0  4
1  3
2  2
3  1
  DB<4> unshift @e,  $_ for @c;

  DB<5> x @e
0  4
1  3
2  2
3  1
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Thank you @Laurent R ,you help me out.And thanks to others for their valuable suggestion

Do you know what  @foo = $bar does?

Let's try it

#!/usr/bin/perl --
use strict;
use warnings;
use Data::Dump qw/ dd pp /;
my @foo = 1..3;
dd\@foo;
@foo = 7..9;
dd\@foo;
@foo = 4;
dd\@foo;
@foo = 2;
dd\@foo;
@foo = ( 4, @foo );
dd\@foo;
__END__
[1, 2, 3]
[7, 8, 9]
[4]
[2]
[4, 2]
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Do you get the problem now ?

perlintro#Arrays shows/links some interesting functions like reverse, and http://perldoc.perl.org/index-functions-by-cat.html#Functions-for-real-@ARRAYs lists some more, as do various Tutorials/manuals in Data Type: Array

$ perl beans
Global symbol "$index" requires explicit package name at beans line 11
+.
Execution of beans aborted due to compilation errors.
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Whoops, looks like you need to clean your room better :)

#!/usr/bin/perl

use strict;

my @number;
my @rev;
@number = (1,2,3,4);
my $index1 = @number;
my $revIndex = 0;
my $x = 0;
for ($x= 0; $x < $index1 ; $x+= 1)
    { 
        
        $revIndex = $index1 - $x;
        $rev[$revIndex] = $number[$x];
        
#case1#
 print "@rev \n" ;
}
#case2# 
print "@rev \n";
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Hi Michael,but its output is some type of pyramid means,when I ran your code I got

  
    1 
   2 1 
  3 2 1 
 4 3 2 1 
 4 3 2 1
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But I need reverse of it,anyway thanks for it

Just remove the print statement inside the for loop, and you will no longer get this "pyramid". I think this print statement was put there just to show you how the array get progressively populated.

Thanks Michael,Its working fine