please help debug and explain

// This program counts how many sales are made // in each of five categories of products start Declarations num category num SIZE = 5 num QUIT = 9 num sales[SIZE] = 0, 0, 0, 0, 0 string HEAD1 = "Sales" string HEAD2 = "Category Number of Sales" output "Enter category ", QUIT, " to quit " input category while category = QUIT if category > 1 AND category < SIZE then sales[category - 1] = sales[category - 1] + 1 else output "Invalid category" endif endwhile output HEAD1 output HEAD2 while category < SIZE output category + 1, sales[category] category = category + 1 endwhile stop