You should add a feature to see the output and the expected output of a submission of course only in the practice session. It saves a lot of time to figure out where we are going wrong. Most of the times it is wrong because of stupid reasons like a missing newline, capitalization etc.
For most of the problems correct format of output can easily be understood by the sample input and output given in the problem , this is something you learn out of little experience .
Still adding of this feature can save many people, many hours of frustration.