I'm getting NAN out of nowhere

[Binarydepth via Digitalmars-d-learn]

On Saturday, 11 July 2015 at 16:57:55 UTC, flamencofantasy wrote:
> On Thursday, 9 July 2015 at 15:14:43 UTC, Binarydepth wrote:
>> This is my code :
>> import std.stdio : writeln, readf;
>> void main()	{
>> 	int[3] nums;
>> 	float prom;
>> 	foreach(nem; 0..2)	{
>> 		writeln("input a number : ");
>> 		readf(" %d", &nums[nem]);
>> 		prom+=nums[nem];
>> 	}
>> 	writeln(prom/3.0);
>> }
>>
>> I get prompted two times for a number and I then get NAN out 
>> of nowhere.
>
> foreach(nem; 0..3)

Yes, Thank you!!