# Function literals -- strange behavior

Ary Borenszweig ary at esperanto.org.ar
Thu Dec 4 12:06:48 PST 2008

```Ary Borenszweig wrote:
> Justin wrote:
>> I recently discovered D's function literals and wrote a small test to
>> explore them. The following code prints out a 15, then a 0. It seems
>> to me that the second should be 64 and not 0. Can anyone explain what
>> I'm doing wrong?
>>
>> module functionliteral;
>> import std.stdio;
>>
>> static void main() {
>>
>>     int[] values = [1,2,4,8];
>>     writefln(Reduce(values, function int(int x, int y) { return x + y;
>> }));
>>     writefln(Reduce(values, function int(int x, int y) { return x * y;
>> }));
>> }
>>
>> static int Reduce(int[] values, int function(int x, int y) operation) {
>>     int total;
>
> That is:
>
> total = 0
>
> That's why in the second case it's like you are doing:
>
> 0*1*2*3*4

Well... 0*1*2*4*8

>
> A reduce function normally takes the first value to use to reduce the
> others. So "total" would be an argument to your reduce function.
>
>
>>     foreach (int v; values)
>>         total = operation(total,v);