... calculate the sum of 1^2 + 2^2 + 3^2 + …. + n^2,(these are exponents) ...
$sum = 1**2+2**2+3**2+4**2+5**2+6**2+7**+$n**2;
... my calculation is wrong the results is not what it should be, why?
You've left out the …. part of the summation specification from the
$sum = 1**2+2**2+3**2+4**2+5**2+6**2+7**+$n**2;
statement (update: which is in error in any event: what is the 7**+$n**2 term supposed to represent?). If n were 15, where are 8, 9, 10, 11, 12, 13, 14 in the sequence of numbers to be squared and summed?
c:\@Work\Perl\monks>perl wMstrict le
"use Data::Dump qw(dd);
use List::Util qw(sum reduce);
;;
my $n = 15;
dd 1 .. $n;
dd map $_**2, 1 .. $n;
dd sum map $_**2, 1 .. $n;
;;
use vars qw($a $b);
dd reduce { $a + $b**2 } 1 .. $n;
"
(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
(1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225)
1240
1240
I haven't tested it, but NetWallah's solution looks right.
Update: See Range Operators in perlop for the .. operator in list context.
Update 2: I actually missed the whole
for ('$i=0; <= $n; $i++')
{
$sum += $i;
}
piece of the OPed code, but that's ok because without strictures and warnings enabled, it's just a noop in the final execution. :)
Update 3: Changed example code to use ranges of 1 .. $n with $n initialized to 15 instead of literal 1 .. 15 ranges; makes the point a little better. Also added the reduce example.
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