hi, my lecturer give me this code and he want the student be bug hunter but i don't know where is the error and why [closed]

void move_q_down(start,Q) { int i = (Q -> rear >= Q->front)? Q->rear : Q->rear + Max;

for(;i > start;i--) Q->P[(i+1)%Max] = Q->P[i%Max]; }

thankyou