Ok, I wanted to show the glob combination gizmo and the spec wasn't perfect.
For permutations 3 of a set of 5, consider the following.
No element is repeated, meaning no element of the input array appears more than once per "sum"
I just sorted the output in my program editor rather than adding that feature to the Perl code. 
#!/usr/bin/perl 
use strict;
use warnings;
use Algorithm::Permute;

my $p = Algorithm::Permute->new(['a','b','c','d','e'], 3);
 
while (my @res = $p->next) 
{
   print join("+", @res), "\n";
}
__END__
# I just used my editor to sort the output
# adapt the above code as you wish

a+b+c
a+b+d
a+b+e
a+c+b
a+c+d
a+c+e
a+d+b
a+d+c
a+d+e
a+e+b
a+e+c
a+e+d
b+a+c
b+a+d
b+a+e
b+c+a
b+c+d
b+c+e
b+d+a
b+d+c
b+d+e
b+e+a
b+e+c
b+e+d
c+a+b
c+a+d
c+a+e
c+b+a
c+b+d
c+b+e
c+d+a
c+d+b
c+d+e
c+e+a
c+e+b
c+e+d
d+a+b
d+a+c
d+a+e
d+b+a
d+b+c
d+b+e
d+c+a
d+c+b
d+c+e
d+e+a
d+e+b
d+e+c
e+a+b
e+a+c
e+a+d
e+b+a
e+b+c
e+b+d
e+c+a
e+c+b
e+c+d
e+d+a
e+d+b
e+d+c

[download]

In reply to Re^3: Sum of N elements in an M element array by Marshall
in thread Sum of N elements in an M element array by abhay180

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.