Nothing hard as such was asked in ZOHO off campus recruitment held in January. Most of the question are from pointers and arrays types. For this c output questions have to be prepared well from geeks section itself. For the second part that is the aptitude part mostly the questions were from puzzles that are their is geeks puzzles section, problems on ages, probability, time and word.
Study hard the questions are such that if you are familiar with all the concepts of arrays, string and pointers then any one can crack the first round.