Why are you passing an array to displayLottery (in the declaration), it's not used in the method? Also, when you set the lottery you are only setting index # 6. And if you had properly passed your array from main it would be an out of range index (which will throw an exception).

Also, when you generate random numbers, use a mod (%) operator, not a * operator. I may be wrong, but I think it's possible for this to generate a int so big that it's bigger than an int's range. rand() % (MAX + 1) will generate a number between 0 and MAX, inclusive.