What will happen if I concatenate one-hot-encoded class along with features? Here is one row from my data:
H  7.042 5.781 5.399  -9.118   5.488  7.470

The first column is the class. The rest of them are features.
I encoded the classes using one-hot-encoding, concatenated them with the feature list:
    1   0  1  7.042 5.781 5.399  -9.118   5.488  7.470

Then I used this list for training.
Am I achieving anything really useful here?

If you include the target in your features, the neural network will use that feature. It's no use unless you're conducting a very specific experiment with neural networks to see if they'll be able to pick it up; which I doubt any would miss.
