Constantly getting outofboundsexception

[NMandrelas]

I posted a question on stack overflow but this group should be a better place for the question.

The question is here : https://stackoverflow.com/questions/44302667/accord-machine-learning-knn-decide-indexoutofrangeexception 

Can someone help me understand what's going wrong ? It's driving me crazy

[NMandrelas]

So ,the answer to this particular problem is weird , and I couldn't find it in the documentation of the knn algorithm. 
The problem was that outputs on knn.Learn part must start with 0 and be counting upwards . Converting capital character to int gave me a minimum of 65 ('A') , I changed the first of the code

                outputs[list_counter] = (char.Parse(training_set[list_counter].letter)) -65 ;

and now everything runs like clockwork!