Product of Array

Compute the product of the elements of an Array

C#

 int value = 1;
 int[] arg = { 1,2,3,4,5 };
 int arg_length = arg.Length;
 
 for( int i = 0; i < arg_length; i++ )
    value *= arg[i];

Alternate

int prod = 1;
int[] arg = { 1, 2, 3, 4, 5 };
foreach (int value in arg) prod *= value;

C++

 int value = 1;
 int arg[] = { 1,2,3,4,5 };
 int arg_length = sizeof(arg)/sizeof(arg[0]);
 int *end = arg+arg_length;
 
 for( int *p = arg; p!=end; ++p )
    value *= *p;

FreeBASIC

 dim array(4) as integer = { 1, 2, 3, 4, 5 }
 
 dim product as integer = 1
 for index as integer = lbound(array) to ubound(array)
   product *= array(index)
 next

Haskell

 let x = [1..10]
 product x      -- the easy way
 foldl (*) 1 x  -- the hard way

Java

 int[] arg = { 1,2,3,4,5 };
 int value = 1;
 for (int i: arg)
    value *= arg;

OCaml

 let x = [|1; 2; 3; 4; 5; 6; 7; 8; 9; 10|];;
 Array.fold_left ( * ) 1 x

Variant, using a liked list rather than an array:

 let x = [1; 2; 3; 4; 5; 6; 7; 8; 9; 10];;
 List.fold_left ( * ) 1 x

PHP

 $array = array(1, 2, 3);
 $sum = array_sum($array);
 echo($sum);

Alternate

 $array = array(1, 2, 3);
 $sum = 0;
 foreach($array as $key)
 {
    $sum += $key;
 }
 echo($sum);

Perl

Interpeter: Perl

my $var;
my @list = (1, 2, 3);
map($var *= $_, @list);

Alternate

my $var;
my @list = (1, 2, 3);
$var *= $_ for (@list);

Python

Interpreter: Python 2.5

 x = [1, 2, 3, 4, 5, 6, 7, 8, 9]
 product = 1
 for i in x:
     product *= i

or

 reduce(lambda z, y: z * y, x)

Note: It is encouraged not to use this as reduce may go away in the future.

Ruby

 ary = [1,2,3,4,5]
 product = ary.inject{|currentProduct,element|currentProduct*element}
 # => 120

Scheme

 (define x '(1 2 3 4 5))
 (apply * x)

Standard ML

 val x = [1,2,3,4,5]
 foldl (op*) 1 x