Java Reference
In-Depth Information
•
Allow the user to enter a name.
•
If the name exists in the map, then output all usernames that are one link away
from the user entered.
•
If the name exists in the map, then output all usernames that are two links away
from the user entered. To accomplish this in a general way, you might consider
writing a recursive subroutine.
Do not forget that your
User
class must override the
hashCode
and
equals
methods.
8. You have collected a file of movie ratings where each movie is rated from 1 (bad)
to 5 (excellent). The first line of the file is a number that identifies how many rat-
ings are in the file. Each rating then consists of two lines: the name of the movie
followed by the numeric rating from 1 to 5. Here is a sample rating file with four
unique movies and seven ratings:
7
Harry Potter and the Half-Blood Prince
4
Harry Potter and the Half-Blood Prince
5
Army of the Dead
1
Harry Potter and the Half-Blood Prince
4
Army of the Dead
2
The Uninvited
4
Pandorium
3
Write a program that reads a file in this format, calculates the average rating for
each movie, and outputs the average along with the number of reviews. Here is the
desired output for the sample data:
Harry Potter and the Half-Blood Prince: 3 reviews, average of 4.3 / 5
Army of the Dead: 2 reviews, average of 1.5 / 5
The Uninvited: 1 review, average of 4 / 5
Pandorium: 1 review, average of 3 / 5
Use a
HashMap
or multiple
HashMaps
to calculate the output. Your map(s) should
index from a string representing each movie's name to integers that store the num-
ber of reviews for the movie and the sum of the ratings for the movie.
9. The file
words.txt
included on the website contains a list of 87,314 English words.
Write a program that uses this word list to implement a simple spell-checker. First,
read all of the words into a
HashSet<String>
object. Then, allow the user to enter
the name of a text file that contains written English. The program should output
all of the words that are not in the set as potentially misspelled words.
